CVE-2024-35860bpf: support deferring bpf_link dealloc to after RCU grace period
- 7.8HighCVSS base score
- 0.24%Exploitation in 30 daysEPSS · top 85% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: support deferring bpf_link dealloc to after RCU grace period BPF link for some program types is passed as a "context" which can be used by those BPF programs to look up additional information. E.g., for multi-kprobes and multi-uprobes, link is used to fetch BPF cookie values. Because of this runtime dependency, when bpf_link refcnt drops to zero there could still be active BPF programs running accessing link data. This patch adds generic support to defer bpf_link dealloc callback to after RCU GP, if requested. This is done by exposing two different deallocation callbacks, one synchronous and one deferred. If deferred one is provided, bpf_link_free() will schedule dealloc_deferred() callback to happen after RCU GP. BPF is using two flavors of RCU: "classic" non-sleepable one and RCU tasks trace one. The latter is used when sleepable BPF programs are used. bpf_link_free() accommodates that by checking underlying BPF program's sleepable flag, and goes either through normal RCU GP only for non-sleepable, or through RCU tasks trace GP *and* then normal RCU GP (taking into account rcu_trace_implies_rcu_gp() optimization), if BPF program is sleepable. We use this for multi-kprobe and multi-uprobe links, which dereference link during program run. We also preventively switch raw_tp link to use deferred dealloc callback, as upcoming changes in bpf-next tree expose raw_tp link data (specifically, cookie value) to BPF program at runtime as well.
Timeline
ID reserved
By Linux
- 2 days later
· 2 days later
Published
- 2 years later
· 2 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.24% · top 85% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected 0dcac272540613d41c05e89679e4ddb978b612f1 – < ac48dc6ac9240f73bf08d29edf65c2deca93ee5d
- affected 0dcac272540613d41c05e89679e4ddb978b612f1 – < 876941f533e7b47fc69977fc4551c02f2d18af97
- affected 0dcac272540613d41c05e89679e4ddb978b612f1 – < 5d8d447777564b35f67000e7838e7ccb64d525c8
- affected 0dcac272540613d41c05e89679e4ddb978b612f1 – < 1a80dbcb2dbaf6e4c216e62e30fa7d3daa8001ce
- affected 5.18
- unaffected < 5.18
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.26 – ≤ 6.6.*
- unaffected 6.8.5 – ≤ 6.8.*
- unaffected 6.9 – ≤ *
References
References4
- https://git.kernel.org/stable/c/ac48dc6ac9240f73bf08d29edf65c2deca93ee5d (opens in a new tab)
- https://git.kernel.org/stable/c/876941f533e7b47fc69977fc4551c02f2d18af97 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/5d8d447777564b35f67000e7838e7ccb64d525c8 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/1a80dbcb2dbaf6e4c216e62e30fa7d3daa8001ce (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2024-35578 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2024-35860)Record last updated .