CVE-2026-80847
CVE CVE-2026-80847EUVD EUVD-2026-71297Published 2026-09-04T15:54:57.000ZLast changed 2026-09-11T09:57:09.000Z
What the advisory describes
In the Linux kernel, the following vulnerability has been resolved: tcp: clamp route advmss to TCP_MIN_MSS tcp_select_initial_window() assumes that callers never pass an MSS smaller than 1, but route-derived advmss values can violate that assumption. A too-small explicit RTAX_ADVMSS is one way to get there, but it is not the only one. The same divide-by-zero can also be reached through the "default advmss" path when RTAX_ADVMSS is left at 0 and the effective advmss is later driven down by route MTU and min_adv_mss. Introduce a tcp_dst_advmss() helper that clamps route advmss to TCP_MIN_MSS before TCP consumes it, and use it in the TCP paths that derive advmss from dst metrics. This keeps the effective MSS from dropping to zero before tcp_select_initial_window() rounds the receive window.
Source: EUVD (ENISA), in the words of the advisory.
Products the advisory names
These come from the advisory itself, not from any check we performed.
- Linux — Linux patch: 7.3-rc1; 2.6.12; patch: 7.2.3; patch: 0; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <31cf2349361902769dc323e4dbf4b449795ec288; patch: 7.1.13; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6b8c20bf61924dfc38fefb145c9f7406d73fae53; patch: 6.18.51; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <870a9e42ecc6fe1b8c25d87af043cb0d9c178fe1; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <cfb44c6028e6f979720315e0772bbd0d4d33ed61
The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.
Carried in the product catalogue
An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.
- Linux — Linux
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