CVE-2026-46323: Linux kernel · net: gro: don't merge zcopy skbs
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in e334cbf3388fd9334503a778a82d9e9f14dd2f71 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:18 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in e334cbf3388fd9334503a778a82d9e9f14dd2f71, 479084ae0e1d9cb7929cb4298d35623de189f80a, 44bea2032af0425e4ce6d26a8af0ede79db49ec1 +3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 9 Jun 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
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
In the Linux kernel, the following vulnerability has been resolved: net: gro: don't merge zcopy skbs skb_gro_receive() can currently copy frags between the source and GRO skb, without checking the zerocopy status, and in particular the SKBFL_MANAGED_FRAG_REFS flag. When SKBFL_MANAGED_FRAG_REFS is set, the skb doesn't hold a reference on the pages in shinfo->frags. Appending those frags to another skb's frags without fixing up the page refcount can lead to UAF. When either the last skb in the GRO chain (the one we would append frags to) or the source skb is zerocopy, don't merge the skbs.
References
- git.kernel.org/stable/c/3c6cc9f2ca65b6dd61b1af75452dc0e1cd0aad8d (opens in a new tab)
- git.kernel.org/stable/c/1f9c828556416fbe3f49386708ce999fc4d4da06 (opens in a new tab)
- git.kernel.org/stable/c/479084ae0e1d9cb7929cb4298d35623de189f80a (opens in a new tab)
- git.kernel.org/stable/c/e334cbf3388fd9334503a778a82d9e9f14dd2f71 (opens in a new tab)
- git.kernel.org/stable/c/44bea2032af0425e4ce6d26a8af0ede79db49ec1 (opens in a new tab)
- git.kernel.org/stable/c/4db79a322db8c97f7b73b8a347395ef4d685eb40 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-46323 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2479832 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46323.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:47727 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:44230 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:44231 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:44259 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:44262 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:27731 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:44270 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:27735 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:27708 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:36018 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:62642 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:62639 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:62641 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:62640 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-784472.html (opens in a new tab)