Linux: Integer Underflow (Wrap or Wraparound)
CVE-2026-31417 is a high-severity integer underflow (wrap or wraparound) vulnerability in Linux, with a CVSS 3.1 base score of 7.5 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 96fc16370b0bceb289c7e0479bd0540b81e257aa, 798d613afb64b01a203f448fb0f43c37c6afe79d, 6e568835ea54a3e1d08e310e34f95d434e739477 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 0.47% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 96fc16370b0bceb289c7e0479bd0540b81e257aa or 798d613afb64b01a203f448fb0f43c37c6afe79d or 6e568835ea54a3e1d08e310e34f95d434e739477 or 1734bd85c5e0a7a801295b729efb56b009cb8fc3, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.168 or 6.6.134, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 96fc16370b0bceb289c7e0479bd0540b81e257aa; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 798d613afb64b01a203f448fb0f43c37c6afe79d; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 6e568835ea54a3e1d08e310e34f95d434e739477; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 1734bd85c5e0a7a801295b729efb56b009cb8fc3; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 4e2d1bcef78d21247fe8fef13bc7ed95885df2b5; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 8c92969c197b91c134be27dc3afb64ab468853a9; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, f953f11ccf4afe6feb635c08145f4240d9a6b544; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, a1822cb524e89b4cd2cf0b82e484a2335496a6d9; and 1 more ranges | 96fc16370b0bceb289c7e0479bd0540b81e257aa, 798d613afb64b01a203f448fb0f43c37c6afe79d, 6e568835ea54a3e1d08e310e34f95d434e739477, 1734bd85c5e0a7a801295b729efb56b009cb8fc3, 4e2d1bcef78d21247fe8fef13bc7ed95885df2b5, 8c92969c197b91c134be27dc3afb64ab468853a9 |
| Siemens | SIMATIC 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 later | Not stated |
| Siemens | SIMATIC 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 later | Not stated |
| Siemens | SIMATIC 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 later | Not stated |
| Siemens | SIMATIC 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 later | Not stated |
| Siemens | SIPLUS 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 later | Not stated |
| Linux | Linux Kernel | 2.6.12.1 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, 6.1.168; 6.2 up to, but not including, 6.6.134; 6.7 up to, but not including, 6.12.81; 6.13 up to, but not including, 6.18.22; 6.19 up to, but not including, 6.19.12; 2.6.12; and 1 more ranges | 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22 |
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
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: net/x25: Fix overflow when accumulating packets Add a check to ensure that `x25_sock.fraglen` does not overflow. The `fraglen` also needs to be resetted when purging `fragment_queue` in `x25_clear_queues()`.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Integer Underflow (Wrap or Wraparound)
The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.
More Integer Underflow (Wrap or Wraparound) vulnerabilities (CWE-191)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/1734bd85c5e0a7a801295b729efb56b009cb8fc3
- git.kernel.org/stable/c/4e2d1bcef78d21247fe8fef13bc7ed95885df2b5
- git.kernel.org/stable/c/6e568835ea54a3e1d08e310e34f95d434e739477
- git.kernel.org/stable/c/798d613afb64b01a203f448fb0f43c37c6afe79d
- git.kernel.org/stable/c/8c92969c197b91c134be27dc3afb64ab468853a9
- git.kernel.org/stable/c/96fc16370b0bceb289c7e0479bd0540b81e257aa
- git.kernel.org/stable/c/a1822cb524e89b4cd2cf0b82e484a2335496a6d9
- git.kernel.org/stable/c/f953f11ccf4afe6feb635c08145f4240d9a6b544
Other references
Recent Integer Underflow (Wrap or Wraparound) vulnerabilities
- 7.1 High severity
- 8.1 High severity
- 7.5 High severity
- 7.5 High severity
- 9.1 Critical severity
- 7.8 High severity
Spotted an error? Tell us.