CVE-2026-98061
- Source
- https://cve.org/CVERecord?id=CVE-2026-98061
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98061.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-98061
- Downstream
- Published
- 2026-09-25T10:24:06Z
- Modified
- 2026-09-26T03:48:32Z
- Summary
- bpf: Reject tail calls directly from callback frames
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject tail calls directly from callback frames
A tail call from a non-zero frame is modeled as a return from that frame. The verifier makes R0 unknown and calls prepare_func_exit() for the taken branch.
When the current frame is a synchronous callback, prepare_func_exit() enforces the callback return-value contract and marks R0 precise. Since the tail-call path synthesized R0 rather than deriving it from an instruction, precision backtracking reaches the callback-calling instruction with R0 still requested and triggers the "callback unexpected regs" verifier bug. A CAP_BPF task can therefore cause a WARN and an -EFAULT BPF_PROG_LOAD.
Tail calls reachable from callbacks are already rejected later by check_max_stack_depth(). Reject a tail call made directly by a callback before constructing the inconsistent return state, using the existing diagnostic. Tail calls from ordinary subprograms keep their current behavior.
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98061.json" }- References
-
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/266aa4ad0b2e82397cd9045752c9bff03d98eddd
- https://git.kernel.org/stable/c/617c8266e49f45747f71e74177646a63f72b7025
- https://git.kernel.org/stable/c/96d31b28263c429a56e4de85bcf744a5c320b3a3
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98061.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-98061
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduceda6c22c91b6284e4713c0cf5b20ab3c9c71b77ae8Fixed617c8266e49f45747f71e74177646a63f72b7025
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducede3245f8990431950d20631c72236d4e8cb2dcde8Fixed96d31b28263c429a56e4de85bcf744a5c320b3a3Fixed266aa4ad0b2e82397cd9045752c9bff03d98eddd
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.18.2Fixed6.18.53