CyberSecBulletin
CVE-2026-31659NVD status: Modified

Linux: Integer Overflow or Wraparound

Published Updated By the CyberSecBulletin desk

CVE-2026-31659 is a critical-severity integer overflow or wraparound vulnerability in Linux, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 7e5d007e0df946bffb8542fb112e0044014a5897, 2997f4bd1f982e7013709946e00be89b507693fa, 95c71365a2222908441b54d6f2c315e0c79fcec3 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux to 7e5d007e0df946bffb8542fb112e0044014a5897 or 2997f4bd1f982e7013709946e00be89b507693fa or 95c71365a2222908441b54d6f2c315e0c79fcec3 or 69d61639bc7e963c3b645e570279d731e7c89062, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.169 or 6.6.135, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux7ea7b4a142758deaf46c1af0ca9ceca6dd55138b up to, but not including, 7e5d007e0df946bffb8542fb112e0044014a5897; 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b up to, but not including, 2997f4bd1f982e7013709946e00be89b507693fa; 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b up to, but not including, 95c71365a2222908441b54d6f2c315e0c79fcec3; 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b up to, but not including, 69d61639bc7e963c3b645e570279d731e7c89062; 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b up to, but not including, f970646b9a39539d1bac86822ac78b5915455ea9; 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b up to, but not including, de6c1dc3c7d01a152607e6fcecee4d5288283f10; 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b up to, but not including, cf2199171ef799ca7270019125f4a91bd20ad4d9; 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b up to, but not including, 3a359bf5c61d52e7f09754108309d637532164a6; and 1 more ranges7e5d007e0df946bffb8542fb112e0044014a5897, 2997f4bd1f982e7013709946e00be89b507693fa, 95c71365a2222908441b54d6f2c315e0c79fcec3, 69d61639bc7e963c3b645e570279d731e7c89062, f970646b9a39539d1bac86822ac78b5915455ea9, de6c1dc3c7d01a152607e6fcecee4d5288283f10
LinuxLinux Kernel3.13.1 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.169; 6.2 up to, but not including, 6.6.135; 6.7 up to, but not including, 6.12.82; 6.13 up to, but not including, 6.18.23; 6.19 up to, but not including, 6.19.13; 3.13; and 1 more ranges5.10.253, 5.15.203, 6.1.169, 6.6.135, 6.12.82, 6.18.23

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: batman-adv: reject oversized global TT response buffers batadv_tt_prepare_tvlv_global_data() builds the allocation length for a global TT response in 16-bit temporaries. When a remote originator advertises a large enough global TT, the TT payload length plus the VLAN header offset can exceed 65535 and wrap before kmalloc(). The full-table response path still uses the original TT payload length when it fills tt_change, so the wrapped allocation is too small and batadv_tt_prepare_tvlv_global_data() writes past the end of the heap object before the later packet-size check runs. Fix this by rejecting TT responses whose TVLV value length cannot fit in the 16-bit TVLV payload length field.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

How developers prevent this class of flaw

  • Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. If possible, choose a language or compiler that performs automatic bounds checking.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Use libraries or frameworks that make it easier to handle numbers without unexpected consequences. Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

More Integer Overflow or Wraparound vulnerabilities (CWE-190)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Integer Overflow or Wraparound vulnerabilities

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