Answer in brief
CVE-2026-80793 records a Unknown severity vulnerability in ipv4: reject undersized MTUs in ip_do_fragment(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a716a64a4ba68cd46f2745fba2b1099fe8e0aa59 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <515b6816ba0c12d8415c88e5f41e6ec029e35cfa || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <74ce7389f8f562d39015f59a00ef7ad6acd37803 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b0ea911453ce7210e8200a07a94d2458bd1e6430 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <36e0741833bd823866f8cb9f112f37cea1a70b60 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d9d1a676b033acabf8e5645f730486d1f8204a3f || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3556beb8ca86677af2aca5bfbed6f8e790fccc83 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c8a74adccaf028223054633b532593101dfcc581 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c0726f0caf8c6b3208552949e17d23634a2f3129 | a716a64a4ba68cd46f2745fba2b1099fe8e0aa59, 515b6816ba0c12d8415c88e5f41e6ec029e35cfa, 74ce7389f8f562d39015f59a00ef7ad6acd37803, b0ea911453ce7210e8200a07a94d2458bd1e6430, 36e0741833bd823866f8cb9f112f37cea1a70b60, d9d1a676b033acabf8e5645f730486d1f8204a3f, 3556beb8ca86677af2aca5bfbed6f8e790fccc83, c8a74adccaf028223054633b532593101dfcc581, c0726f0caf8c6b3208552949e17d23634a2f3129 |
| Linux/Linuxgeneric | 2.6.12 | Not reported |
Published upstream
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 4, 2026
In the Linux kernel, the following vulnerability has been resolved: ipv4: reject undersized MTUs in ip_do_fragment() ip_do_fragment() subtracts the IPv4 header length from the effective MTU and passes the resulting payload MTU to ip_frag_next(). If the effective MTU is smaller than hlen + 8, ip_frag_next() rounds the fragment payload length down to zero. The fragmentation state then never makes forward progress: state->left, state->ptr and state->offset stay unchanged while ip_do_fragment() keeps allocating and transmitting header-only fragments until the softlockup detector fires. This is reproducible with a route installed using "mtu lock 20", but it is also reproducible without route MTU lock, for example by forwarding a packet to a device whose MTU is 20. Fix it in ip_do_fragment() by rejecting mtu < hlen + 8 with -EMSGSIZE, matching the existing IPv6 fragmentation check.
Quoted source text, attributed separately from HOL analysis.