CyberSecBulletin
CVE-2026-23457NVD status: Modified

Linux: Integer Overflow or Wraparound

Published Updated By the CyberSecBulletin desk

CVE-2026-23457 is a high-severity integer overflow or wraparound vulnerability in Linux, with a CVSS 3.1 base score of 8.6 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 ed81b6a7012485acdb9c6c80735a0b7d8e5e1873, cd1b7403ec835f8a0b3f1f7e68ac26af2cb1e42f, b75209debb9adab287b3caa982f77788c1e15027 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 0.45% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to ed81b6a7012485acdb9c6c80735a0b7d8e5e1873 or cd1b7403ec835f8a0b3f1f7e68ac26af2cb1e42f or b75209debb9adab287b3caa982f77788c1e15027 or 528b4509c9dfc272e2e92d811915e5211650d383, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.167 or 6.6.130, 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
LinuxLinuxf5b321bd37fbec9188feb1f721ab46a5ac0b35da up to, but not including, ed81b6a7012485acdb9c6c80735a0b7d8e5e1873; f5b321bd37fbec9188feb1f721ab46a5ac0b35da up to, but not including, cd1b7403ec835f8a0b3f1f7e68ac26af2cb1e42f; f5b321bd37fbec9188feb1f721ab46a5ac0b35da up to, but not including, b75209debb9adab287b3caa982f77788c1e15027; f5b321bd37fbec9188feb1f721ab46a5ac0b35da up to, but not including, 528b4509c9dfc272e2e92d811915e5211650d383; f5b321bd37fbec9188feb1f721ab46a5ac0b35da up to, but not including, 75fcaee5170e7dbbee778927134ef2e9568b4659; f5b321bd37fbec9188feb1f721ab46a5ac0b35da up to, but not including, 865dba58958c3a86786f89a501971ab0e3ec6ba9; f5b321bd37fbec9188feb1f721ab46a5ac0b35da up to, but not including, d4f17256544cc37f6534a14a27a9dec3540c2015; f5b321bd37fbec9188feb1f721ab46a5ac0b35da up to, but not including, fbce58e719a17aa215c724473fd5baaa4a8dc57c; and 1 more rangesed81b6a7012485acdb9c6c80735a0b7d8e5e1873, cd1b7403ec835f8a0b3f1f7e68ac26af2cb1e42f, b75209debb9adab287b3caa982f77788c1e15027, 528b4509c9dfc272e2e92d811915e5211650d383, 75fcaee5170e7dbbee778927134ef2e9568b4659, 865dba58958c3a86786f89a501971ab0e3ec6ba9
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
LinuxLinux Kernel2.6.34 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, 6.1.167; 6.2 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.78; 6.13 up to, but not including, 6.18.20; 6.19 up to, but not including, 6.19.10; 7.05.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.20

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
LowSome restricted data can be read.
Integrity
LowLimited modification of data is possible.
Availability
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp() sip_help_tcp() parses the SIP Content-Length header with simple_strtoul(), which returns unsigned long, but stores the result in unsigned int clen. On 64-bit systems, values exceeding UINT_MAX are silently truncated before computing the SIP message boundary. For example, Content-Length 4294967328 (2^32 + 32) is truncated to 32, causing the parser to miscalculate where the current message ends. The loop then treats trailing data in the TCP segment as a second SIP message and processes it through the SDP parser. Fix this by changing clen to unsigned long to match the return type of simple_strtoul(), and reject Content-Length values that exceed the remaining TCP payload length.

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: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Integer Overflow or Wraparound vulnerabilities

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