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CVE-2026-97964

ppp_synctty: ensure a writeable skb header

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, and 1 more
None on Exploit-DB, Metasploit or GitHub

Summary

In 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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 4cf476ced45d7f12df30a68e833b263e7a2202d1 · fixed in 25e03eeead2c49748c7582dfb64c205f93a42d00; From 4cf476ced45d7f12df30a68e833b263e7a2202d1 · fixed in a256f9925288ef47de8febed5c38d5cc21340211; From 4cf476ced45d7f12df30a68e833b263e7a2202d1 · fixed in 7953946f68262a8bb137aa101249adef6e029652; From 4cf476ced45d7f12df30a68e833b263e7a2202d1 · fixed in 3af7797fbabc84992e0ca5ad2bc0ca8537d053ef; From 4cf476ced45d7f12df30a68e833b263e7a2202d1 · fixed in 0996c3e6bcc6ae08cb371ed43648c9f7f748ae6e; From 4cf476ced45d7f12df30a68e833b263e7a2202d1 · fixed in 15d0a6c9a42df2d745c37510dba828f6dbe60d9f; From 4cf476ced45d7f12df30a68e833b263e7a2202d1 · fixed in 8aaeb56aff2a557a88f83ae866da2c91ad247e59

  • Linux Linux

    5.11

  • KernelLinux

    From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53; From 6.19.0 · fixed in 7.2.7

References 7

git.kernel.org