CVE-2026-97964: Linux kernel · ppp_synctty: ensure a writeable skb header
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 13:47 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix has been implemented in the Linux kernel to use skb_cow_head() in ppp_sync_txmunge(), ensuring the skb header is writable before modification. Users should apply the official kernel updates that include this fix. Since this is a kernel-level vulnerability, updating to a patched kernel version is the recommended remediation.
Description
A vulnerability in the Linux kernel's ppp_synctty component was resolved. The function ppp_sync_txmunge() did not ensure the socket buffer (skb) header was writable before modifying it, potentially allowing data corruption when bridging PPP channels. This could occur if a received skb bypassed the usual writable checks, such as when a PPPoE frame shares its buffer with a clone queued to an AF_PACKET socket and is bridged to a synchronous tty channel. The fix involves using skb_cow_head() to guarantee both sufficient headroom and a writable header.
References
- ubuntu.com/security/CVE-2026-97964 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-97964 (opens in a new tab)
- git.kernel.org/stable/c/3af7797fbabc84992e0ca5ad2bc0ca8537d053ef (opens in a new tab)
- git.kernel.org/stable/c/15d0a6c9a42df2d745c37510dba828f6dbe60d9f (opens in a new tab)
- git.kernel.org/stable/c/8aaeb56aff2a557a88f83ae866da2c91ad247e59 (opens in a new tab)
- git.kernel.org/stable/c/0996c3e6bcc6ae08cb371ed43648c9f7f748ae6e (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-97964 (opens in a new tab)
- git.kernel.org/stable/c/25e03eeead2c49748c7582dfb64c205f93a42d00 (opens in a new tab)
- git.kernel.org/stable/c/7953946f68262a8bb137aa101249adef6e029652 (opens in a new tab)
- git.kernel.org/stable/c/a256f9925288ef47de8febed5c38d5cc21340211 (opens in a new tab)