ppp_synctty: ensure a writeable skb header

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-97964
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-25 11:17:24 UTC
Updated2026-09-25 11:17:24 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ppp_synctty: ensure a writeable skb header ppp_sync_txmunge() checks headroom before prepending the address and control bytes, but does not ensure that the skb header is writable. A received skb can reach this function through PPP channel bridging without passing through ppp_start_xmit(), which calls skb_cow_head(). For example, a PPPoE frame may share its buffer with a clone queued to an AF_PACKET socket. If it is bridged to a synchronous tty channel, the address/control bytes can overwrite data still visible to that socket. Use skb_cow_head() to ensure both sufficient headroom and a writable header.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 4cf476ced45d7f12df30a68e833b263e7a2202d1 3af7797fbabc84992e0ca5ad2bc0ca8537d053ef git Not specified
CNA Linux Linux affected 4cf476ced45d7f12df30a68e833b263e7a2202d1 0996c3e6bcc6ae08cb371ed43648c9f7f748ae6e git Not specified
CNA Linux Linux affected 4cf476ced45d7f12df30a68e833b263e7a2202d1 15d0a6c9a42df2d745c37510dba828f6dbe60d9f git Not specified
CNA Linux Linux affected 4cf476ced45d7f12df30a68e833b263e7a2202d1 8aaeb56aff2a557a88f83ae866da2c91ad247e59 git Not specified
CNA Linux Linux affected 5.11 Not specified
CNA Linux Linux unaffected 5.11 semver Not specified
CNA Linux Linux unaffected 6.12.111 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.53 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.7 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/15d0a6c9a42df2d745c37510dba828f6dbe60d9f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8aaeb56aff2a557a88f83ae866da2c91ad247e59 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0996c3e6bcc6ae08cb371ed43648c9f7f748ae6e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3af7797fbabc84992e0ca5ad2bc0ca8537d053ef 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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