CVE-2026-64055: Linux kernel · net: ethernet: cortina: Carry over frag counter
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
A fix has been implemented in the Linux kernel to address this vulnerability by modifying the fragment counter handling in the ethernet cortina driver. Users should update to a kernel version that includes this patch once available. Patch status is not explicitly confirmed in the provided data; check the official Linux kernel advisories or vendor updates for the exact fixed versions and apply the update accordingly.
Description
In the Linux kernel, the following vulnerability has been resolved: net: ethernet: cortina: Carry over frag counter The gmac_rx() NAPI poll function assembles packets in an SKB from a ring buffer. If the ring buffer gets completely emptied during a poll cycle, we exit gmac_rx(), but the packet is not yet completely assembled in the SKB, yet the fragment counter frag_nr is reset to zero on the next invocation. Solve this by making the RX fragment counter a part of the port struct, and carry it over between invocations. Reset the fragment counter only right after calling napi_gro_frags(), on error (after calling napi_free_frags()) or if stopping the port. Reset it in some place where not strictly necessary just to emphasize what is going on. This was found by Sashiko during normal patch review.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64055 (opens in a new tab)
- git.kernel.org/stable/c/46806096f35b8d3dfa2f321ddd77f597edcdb85f (opens in a new tab)
- git.kernel.org/stable/c/7123cf481e21b54eb6adc4cb0d8dc2876aeaee41 (opens in a new tab)
- git.kernel.org/stable/c/75105fcf73f1ce7d9f769aaefec6e6d6645d5ac0 (opens in a new tab)
- git.kernel.org/stable/c/78cf08b3be47c28f07008a76c932bad7cdffa9d8 (opens in a new tab)
- git.kernel.org/stable/c/7af1fabdee744b7995fe01b30b77dfc397657cb5 (opens in a new tab)
- git.kernel.org/stable/c/c373b34877afea61c89e0dd2e38948c624249b9b (opens in a new tab)
- git.kernel.org/stable/c/df31e3b64455293df1ea89c7da7d5c9bfbcdd253 (opens in a new tab)
- git.kernel.org/stable/c/ebd8ec2b309e3a447851b456ccaf8fb39f3661e7 (opens in a new tab)