CVE-2026-46323
CVE-2026-46323 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.
Key facts
- Severity: High (CVSS 3.x base score 7.8)
- EPSS exploit prediction: 0% (3rd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-35413
- Weakness: CWE-416
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-46323?
- 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.
- How severe is CVE-2026-46323?
- CVE-2026-46323 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-46323 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-46323?
- CVE-2026-46323 primarily affects Linux Linux Kernel. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2026-46323?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-46323 have an EU (EUVD) identifier?
- Yes. CVE-2026-46323 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35413.
- When was CVE-2026-46323 published?
- CVE-2026-46323 was published on 2026-06-09 and last updated on 2026-07-08.
References
- https://git.kernel.org/stable/c/1f9c828556416fbe3f49386708ce999fc4d4da06
- https://git.kernel.org/stable/c/3c6cc9f2ca65b6dd61b1af75452dc0e1cd0aad8d
- https://git.kernel.org/stable/c/44bea2032af0425e4ce6d26a8af0ede79db49ec1
- https://git.kernel.org/stable/c/479084ae0e1d9cb7929cb4298d35623de189f80a
- https://git.kernel.org/stable/c/4db79a322db8c97f7b73b8a347395ef4d685eb40
- https://git.kernel.org/stable/c/e334cbf3388fd9334503a778a82d9e9f14dd2f71
- https://access.redhat.com/errata/RHSA-2026:27708
- https://access.redhat.com/errata/RHSA-2026:27731
- https://access.redhat.com/errata/RHSA-2026:27735
- https://access.redhat.com/errata/RHSA-2026:36018
- https://access.redhat.com/security/cve/CVE-2026-46323
- https://bugzilla.redhat.com/show_bug.cgi?id=2479832
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46323.json
Affected products (5)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
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