CVE-2026-64177: Linux kernel · phonet/pep: disable BH around forwarded sk_receive_skb()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · patch available : update Linux kernel when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 20 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
A patch is available and included in updated Linux kernel packages for Ubuntu 20.04 LTS and related distributions. Users should apply the standard system update and reboot to ensure the fix is active. Due to an ABI change, third-party kernel modules must be recompiled and reinstalled after the update. No additional mitigation steps are required beyond applying the official updates.
Description
A medium-severity vulnerability (CVE-2026-64177) in the Linux kernel's phonet/pep networking subsystem was resolved. The issue involved improper handling of bottom halves (BH) around forwarded sk_receive_skb() calls, causing inconsistent socket lock states between process and softirq contexts. This could lead to a system crash (denial of service). Multiple Linux kernel subsystems were updated to address this and other security issues. A patch is available and included in recent Linux kernel updates for affected Ubuntu versions. Users should update and reboot to apply the fixes. No known exploits are reported in the wild.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64177 (opens in a new tab)
- git.kernel.org/stable/c/02c04df84de709060f63e1d52ec67488c4f6f212 (opens in a new tab)
- git.kernel.org/stable/c/8420aa4900417797323dd567ba9d1512280c2dc3 (opens in a new tab)
- git.kernel.org/stable/c/84bc87beb4cd77670939b446326788e4c9b3db37 (opens in a new tab)
- git.kernel.org/stable/c/a3fc8f2dacd1c37325977fc1fbbf3d52141df99e (opens in a new tab)
- git.kernel.org/stable/c/b2606c302d7f2b4ee48da05e32ed60aed1b0cd53 (opens in a new tab)
- git.kernel.org/stable/c/bd795f106b3889fb0706c6e4831c4b27e2b5666b (opens in a new tab)
- git.kernel.org/stable/c/dbc81608e3a653dea6cf403f20cae35468b8ab9c (opens in a new tab)
- git.kernel.org/stable/c/f08c45076e4fd8b0adbc5eb186d6e6a3e7350d7b (opens in a new tab)
- ubuntu.com/security/CVE-2026-64177 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64177 (opens in a new tab)
- git.kernel.org/linus/dbc81608e3a653dea6cf403f20cae35468b8ab9c (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8593-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8610-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8618-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8620-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8620-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8620-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8620-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8663-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8664-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8668-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)