CVE-2026-68296net: gre: fix lltx regression for GRE tunnels with SEQ/CSUM
- —Not scoredno CVSS score yet
- 0.21%Exploitation in 30 daysEPSS · top 89% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: net: gre: fix lltx regression for GRE tunnels with SEQ/CSUM Before commit 00d066a4d4ed ("netdev_features: convert NETIF_F_LLTX to dev->lltx"), NETIF_F_LLTX was set unconditionally in both __gre_tunnel_init() and ip6gre_tnl_init_features() alongside GRE_FEATURES: dev->features |= GRE_FEATURES | NETIF_F_LLTX; When that commit converted NETIF_F_LLTX to the dev->lltx flag, it placed 'dev->lltx = true' after the SEQ/CSUM early returns instead of before them. This causes GRE/GRETAP/ip6gre tunnels with SEQ or CSUM+encap to lose lockless TX, reintroducing _xmit_lock acquisition around their ndo_start_xmit. Since GRE xmit re-enters the stack via ip_tunnel_xmit(), holding _xmit_lock risks ABBA deadlock with the underlay device. CPU0 CPU1 ---- ---- lock(&qdisc_xmit_lock_key#6); lock(&qdisc_xmit_lock_key#3); lock(&qdisc_xmit_lock_key#6); lock(&qdisc_xmit_lock_key#3); Fix by moving dev->lltx = true before the early returns in both functions, restoring the original unconditional behavior.
Timeline
ID reserved
By Linux
- 11 days later
· 11 days later
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.21% · top 89% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 00d066a4d4edbe559ba6c35153da71d4b2b8a383 – < 9f948e9aede9678f4103457daf2bc9dd54c65a06
- affected 00d066a4d4edbe559ba6c35153da71d4b2b8a383 – < 15a1c5f2ed2eeb3daad8d5766fd506aeda4710f3
- affected 00d066a4d4edbe559ba6c35153da71d4b2b8a383 – < 2bffe379023512d280337c70faeb6a8cc435db5e
- affected 00d066a4d4edbe559ba6c35153da71d4b2b8a383 – < 675ed582c1aa4d919dd535490de08c015005c653
- affected 6.12
- unaffected < 6.12
- unaffected 6.12.101 – ≤ 6.12.*
- unaffected 6.18.42 – ≤ 6.18.*
- unaffected 7.1.6 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References4
- https://git.kernel.org/stable/c/9f948e9aede9678f4103457daf2bc9dd54c65a06 (opens in a new tab)
- https://git.kernel.org/stable/c/15a1c5f2ed2eeb3daad8d5766fd506aeda4710f3 (opens in a new tab)
- https://git.kernel.org/stable/c/2bffe379023512d280337c70faeb6a8cc435db5e (opens in a new tab)
- https://git.kernel.org/stable/c/675ed582c1aa4d919dd535490de08c015005c653 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-55397 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-68296)Record last updated .