| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| Integer underflow and out-of-bounds read in the HTTP/2 server DATA frame parser in Apache bRPC allows an unauthenticated remote attacker to cause denial of service by sending a malformed DATA frame with the PADDED flag set and a zero-length payload.
Root Cause:
The HTTP/2 DATA frame handler computed the fragment size from the attacker-controlled payload length and, when the PADDED flag was present, decremented the fragment size before ensuring that the frame contained the mandatory pad length byte. A zero-length padded DATA frame could therefore underflow the unsigned fragment size and read the pad length byte past the end of the frame buffer.
Affected Scenarios:
Apache bRPC servers that accept HTTP/2 traffic are affected when a remote client can send crafted HTTP/2 frames to the server. HTTP/2 may be reached through cleartext h2c detection on an HTTP port or through TLS ALPN negotiation.
How to Fix:
(Choose one of the following options)
1. Upgrade Apache bRPC to version 1.18.0, which fixes this issue.
2. Apply this patch: https://github.com/apache/brpc/pull/3325
Note:
The fix validates that a padded DATA frame has enough payload bytes for the pad length field before decrementing the fragment size or reading the pad length byte. Malformed zero-length padded DATA frames are rejected with HTTP/2 FRAME_SIZE_ERROR. |
| An integer underflow in the mcpack2pb component of Apache bRPC (version < 1.18.0) on all platforms allows remote attackers to crash a bRPC server by sending a request containing a string field with a zero value_size. The UnparsedValue::as_string() function computes `_size - 1` without validating `_size`; when value_size is 0 the expression underflows to SIZE_MAX, resize() throws std::length_error, and because the exception is not caught on the request parsing path the process aborts (SIGABRT).
Root Cause:
In src/mcpack2pb/parser.cpp, UnparsedValue::as_string() resizes the output string to `_size - 1`, where `_size` is the value_size of a string field taken directly from the network data. A value_size of 0 underflows the unsigned size_t, and the subsequent resize() throws an exception that is not caught.
Affected Scenarios:
bRPC servers that accept nshead frames wired to the ubrpc mcpack2 adaptor (for example the NsheadService + UbrpcMcpack2Adaptor deployment pattern) can be crashed by a single unauthenticated request. Stock open-source bRPC registers the ubrpc/nshead_mcpack protocols as client-only, so default server configurations are not affected.
How to Fix:
1. Upgrade bRPC to a version that includes this fix.
2. Apply the patch in PR https://github.com/apache/brpc/pull/3450 |
| Apache Traffic Server can be used to exhaust an HTTP/1.1 origin's worker pool via a malformed padded HTTP/2 DATA frame.
This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, 10.2.0.
Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue. |
| In Eclipse OpenJ9 versions prior to 0.63.0, the JITServer component fails to perform cross-field validation on attacker-controlled `_size`, `_paddingSize`, and `_dataOffset` fields during `DataDescriptor` message deserialization. An unauthenticated remote attacker can send a crafted network payload that triggers an unsigned integer underflow in `DataDescriptor::getPayloadSize()` and `DataDescriptor::getNextDescriptor()`. This results in an out-of-bounds heap read and an immediate process crash (SIGSEGV), causing a denial of service. |
| Integer underflow (wrap or wraparound) in Windows WLAN Service allows an unauthorized attacker to deny service over a network. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: account proxy paths against the mesh path limit
Proxy-path churn can drive the interface path counter negative and let
later mesh path additions exceed MESH_MAX_MPATHS.
mesh_path_free_rcu() decrements the interface mpaths counter for entries
from both the mesh and proxy path tables, but mpp_path_add() never
reserves a slot in that counter. Removing or expiring a proxy path
therefore returns a slot that was never charged.
mesh_path_add() uses the same counter to enforce MESH_MAX_MPATHS, so once
it falls below the number of installed paths the limit no longer holds.
Reserve the shared quota before allocating a proxy path and release it on
every unsuccessful addition. Mesh and proxy paths now share one
1024-entry budget, so mpp_path_add() can return -ENOSPC at that limit. |
| In the Linux kernel, the following vulnerability has been resolved:
iomap: guard io_size EOF trim against concurrent truncate underflow
iomap: fix zero padding data issue in concurrent append writes
changed ioend accounting so that io_size tracks only valid data
within EOF. This trims io_size when a writeback range extends
past end_pos:
ioend->io_size += map_len;
if (ioend->io_offset + ioend->io_size > end_pos)
ioend->io_size = end_pos - ioend->io_offset;
However, if end_pos ends up below ioend->io_offset, the subtraction
becomes negative and is stored in size_t io_size, causing an unsigned
wrap to a huge value. This can happen when writeback continues past
byte-level EOF up to a block-aligned range, or when a concurrent
truncate shrinks the file after end_pos was sampled in
iomap_writeback_handle_eof().
A wrapped io_size can mislead append detection and corrupt
completion-time size handling, since filesystem end_io paths consume
io_size for decisions such as on-disk EOF updates and unwritten/COW
completion ranges.
Fix this by clamping io_size to zero when EOF has moved to or before
the ioend start offset. This preserves the original intent of trimming
io_size to valid in-EOF data while avoiding the underflow. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/hugetlb: fix hugetlb cgroup rsvd charge/uncharge mismatch
In alloc_hugetlb_folio(), a single h_cg pointer is used for both the rsvd
and non-rsvd hugetlb cgroup charges. When map_chg is set,
hugetlb_cgroup_charge_cgroup_rsvd() stores the charged cgroup in h_cg, but
the immediately following hugetlb_cgroup_charge_cgroup() overwrites h_cg
with the non-rsvd cgroup pointer.
As a result, hugetlb_cgroup_commit_charge_rsvd() stores the wrong
(non-rsvd) cgroup pointer into the folio's rsvd slot.
When the folio is later freed, free_huge_folio() unconditionally calls
both hugetlb_cgroup_uncharge_folio() and
hugetlb_cgroup_uncharge_folio_rsvd(). The rsvd uncharge reads back the
wrong cgroup from the folio and decrements a counter that was never
charged for that cgroup, causing a page_counter underflow:
page_counter underflow: -512 nr_pages=512
WARNING: mm/page_counter.c:61 at page_counter_cancel
Fix this by introducing a separate h_cg_rsvd pointer exclusively for the
rsvd charge path, keeping the rsvd and non-rsvd charges fully independent
through their charge, commit, and error uncharge paths. |
| In the Linux kernel, the following vulnerability has been resolved:
staging: rtl8723bs: rtw_mlme: add bounds checks before ie_length subtraction
Add guards to ensure ie_length is large enough before subtracting
fixed IE offsets to prevent unsigned integer underflow. |
| RIOT is an open-source microcontroller operating system designed for Internet of Things devices and other embedded systems. Prior to 2026.07, _parse_reply() in sys/net/application_layer/dhcpv6/client.c omits minimum-length validation before passing IA_PD and IA_NA option bodies to sub-option parsers. A malicious or compromised DHCPv6 server can send a REPLY with an option length smaller than the required structure while MODULE_DHCPV6_CLIENT_IA_PD is enabled, causing _parse_ia_pd_option to read past the option body, size_t underflow, and unbounded out-of-bounds heap reads that can crash the device and may expose or corrupt memory. This issue is fixed in version 2026.07. |
| In the Linux kernel, the following vulnerability has been resolved:
tipc: reject invalid and unexpected GRP_ACK_MSG to prevent bc_ackers underflow
Commit 48a5fe38772b ("tipc: fix bc_ackers underflow on duplicate
GRP_ACK_MSG") rejected duplicate/stale ACKs in tipc_group_proto_rcv()
by returning early when less_eq(acked, m->bc_acked).
However, that check remains incomplete in two ways:
1. When grp->bc_ackers is zero (e.g. on a quiet group, when replicast
ACKs were not requested, or after all expected members have already
acknowledged), an unexpected GRP_ACK_MSG with acked > m->bc_acked
passes less_eq() and unconditionally decrements grp->bc_ackers.
Because bc_ackers is a u16, this wraps to 65535, causing
tipc_group_bc_cong() to permanently report congestion and blocking
all future group broadcasts on the socket.
2. During an active broadcast round (grp->bc_ackers > 0), the sender
transmits packet S and advances grp->bc_snd_nxt to S + 1. Receivers
increment their expected counter to S + 1 upon consuming packet S,
so the only valid ACK value for the current round is strictly
acked == grp->bc_snd_nxt.
However, tipc_group_update_bc_members() initializes each member's
m->bc_acked to prev = grp->bc_snd_nxt - 1 (S - 1 before increment).
This leaves a 2-sequence gap (S - 1 to S + 1) in sequence space.
An incoming ACK is therefore neither rejected as duplicate nor
prevented from decrementing grp->bc_ackers if an unexpected or stale
value (such as S) is received. A member sending acked = S followed
by acked = S + 1 could decrement grp->bc_ackers twice in the same
round, prematurely clearing bc_ackers or underflowing it.
Fix this by:
- Dropping GRP_ACK_MSG immediately if grp->bc_ackers is zero.
- Requiring acked == grp->bc_snd_nxt and rejecting duplicates where
m->bc_acked == acked. Because replicast broadcast rounds are strictly
sequential, only grp->bc_snd_nxt can be acknowledged, and each member
can acknowledge at most once per round.
Note that a related pre-existing issue in tipc_group_delete_member()
(where grp->bc_ackers decrementing to zero upon member departure does
not restore *grp->open or trigger a socket wakeup) will be addressed
in a separate patch. |
| The TLS 1.3 Certificate-message parser in NetX Secure decrements the message length to skip a context byte without first establishing that the message has a byte to skip. A zero-length Certificate message therefore wraps the unsigned length to `0xFFFFFFFF`, which makes the bounds check that follows vacuous and sends the parser reading past the session packet buffer.
The trigger is a four-byte handshake header and requires no cryptographic validity. It is reachable pre-authentication. |
| In the Linux kernel, the following vulnerability has been resolved:
net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6()
skb_maybe_pull_tail() subtracts skb_headlen(skb) from the unsigned max
argument and passes the result to __pskb_pull_tail() as a signed int. The
function does not ensure that max is at least skb_headlen(skb).
This can happen while parsing IPv6 extension headers when an skb already
has a linear area larger than MAX_IPV6_HDR_LEN. Once the parser needs data
beyond the linear area, max - skb_headlen(skb) wraps and is converted to a
negative delta. __pskb_pull_tail() then passes that negative length to
skb_copy_bits(), where it can become a very large copy length.
Pass the requested length itself as the pull bound at the three
extension-header call sites, so the delta can no longer go negative. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix bounds check for skb-backed dynptrs
The skb_pointer_if_linear() function checks whether a
memory region of length len starting at offset off into
the skb is in the linear area, and returns a pointer to
the region if so. The check currently subtracts between
skb_headlen and offset of the check, and since skb_headlen
is unsigned the subtraction can underflow. This causes the
bounds check to spuriously pass and generate an arbitrary
pointer of the form *(skb->data + off).
The only user of this helper is currently skb-backed BPF
dynptr code. Returning the wrong pointer leads to the
dynptr erroneously being backed with invalid memory.
Ensure the subtraction cannot underflow, and fail the check if
it would. Use u64 arithmetic to also prevent overflow when
calculating (skb_headlen(skb) - off) since off is unsigned. |
| [This CNA information record relates to multiple CVEs; the
text explains which aspects/vulnerabilities correspond to which CVE.]
1) XSA-437 (CVE-2023-34321) addressed issues with overflows in
calculations involved in guests flushing caches through
GNTTABOP_cache_flush. Unfortunately the fix there introduced a
calculation which may underflow, resulting in a loop which would - at
least on 64-bit Arm - take excessively long, and which would likely
eventually crash the hypervisor.
This is CVE-2026-102699.
2) GNTTABOP_cache_flush may be issued on memory mapped from another
domain using the grant table interface. However there was no
restriction to disallow the use of invalidate-without-clean against
read-only grant mappings, which may corrupt the granted memory.
This is CVE-2026-102702. |
| [This CNA information record relates to multiple CVEs; the
text explains which aspects/vulnerabilities correspond to which CVE.]
1) XSA-437 (CVE-2023-34321) addressed issues with overflows in
calculations involved in guests flushing caches through
GNTTABOP_cache_flush. Unfortunately the fix there introduced a
calculation which may underflow, resulting in a loop which would - at
least on 64-bit Arm - take excessively long, and which would likely
eventually crash the hypervisor.
This is CVE-2026-102699.
2) GNTTABOP_cache_flush may be issued on memory mapped from another
domain using the grant table interface. However there was no
restriction to disallow the use of invalidate-without-clean against
read-only grant mappings, which may corrupt the granted memory.
This is CVE-2026-102702. |
| Integer underflow (wrap or wraparound) in Windows Failover Cluster allows an unauthorized attacker to deny service over a network. |
| Heap-based buffer overflow in Network Policy Server (NPS) allows an unauthorized attacker to execute code over a network. |
| In the Linux kernel, the following vulnerability has been resolved:
xfs: don't let hidden_space go negative in xfs_metafile_resv_init
LOLLM points out that if the amount of fdblocks that we can reserve for
a metadata btree file goes below the space already used by that file,
then the hidden_space subtraction can underflow, causing
xfs_dec_fdblocks to subtract a huge amount of space. We never want the
target to be less than the used sapce, so fix the logic that adjusts
dblocks_avail downwards.
Also fix an error in the adjacent comment. |
| libsmb2 through 6.2 contains an integer underflow vulnerability in decode_acl that allows malicious SMB servers to trigger heap out-of-bounds reads via crafted security descriptors. Attackers controlling a server or intercepting unsigned sessions can send an AclSize below 8 in a QUERY_INFO reply, bypassing ACE bounds checks and crashing the client. |
