CVE-2026-52916

CVE-2026-52916 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: batman-adv: frag: disallow unicast fragment in fragment batadv_frag_skb_buffer() is called by batadv_batman_skb_recv() when a BATADV_UNICAST_FRAG packet is received. Once all fragments are collected and the packet is reassembled, batadv_recv_frag_packet() calls batadv_batman_skb_recv() again to process the defragmented payload. A malicious sender can craft a BATADV_UNICAST_FRAG packet whose reassembled payload is itself a BATADV_UNICAST_FRAG packet (matryoshka-style nesting). Each nesting level recurses through batadv_batman_skb_recv() without bound, growing the kernel stack until it is exhausted. Since refragmentation or fragments in fragments are not actually allowed, discard all packets which are still BATADV_UNICAST_FRAG packets after the defragmentation process.

Frequently asked questions

What is CVE-2026-52916?
In the Linux kernel, the following vulnerability has been resolved: batman-adv: frag: disallow unicast fragment in fragment batadv_frag_skb_buffer() is called by batadv_batman_skb_recv() when a BATADV_UNICAST_FRAG packet is received. Once all fragments are collected and the packet is reassembled, batadv_recv_frag_packet() calls batadv_batman_skb_recv() again to process the defragmented payload. A malicious sender can craft a BATADV_UNICAST_FRAG packet whose reassembled payload is itself a BATADV_UNICAST_FRAG packet (matryoshka-style nesting). Each nesting level recurses through batadv_batman_skb_recv() without bound, growing the kernel stack until it is exhausted. Since refragmentation or fragments in fragments are not actually allowed, discard all packets which are still BATADV_UNICAST_FRAG packets after the defragmentation process.
How severe is CVE-2026-52916?
CVE-2026-52916 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-52916 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-52916?
CVE-2026-52916 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-2026-52916?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-52916 have an EU (EUVD) identifier?
Yes. CVE-2026-52916 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38719.
When was CVE-2026-52916 published?
CVE-2026-52916 was published on 2026-06-24 and last updated on 2026-07-08.

References

Affected products (5)

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