Description

In the Linux kernel, the following vulnerability has been resolved:

bpf: correctly handle malformed BPF_CORE_TYPE_ID_LOCAL relos

In case of malformed relocation record of kind BPF_CORE_TYPE_ID_LOCAL
referencing a non-existing BTF type, function bpf_core_calc_relo_insn
would cause a null pointer deference.

Fix this by adding a proper check upper in call stack, as malformed
relocation records could be passed from user space.

Simplest reproducer is a program:

r0 = 0
exit

With a single relocation record:

.insn_off = 0, /* patch first instruction */
.type_id = 100500, /* this type id does not exist */
.access_str_off = 6, /* offset of string "0" */
.kind = BPF_CORE_TYPE_ID_LOCAL,

See the link for original reproducer or next commit for a test case.

Classification

CVE ID: CVE-2024-49850

CVSS Base Severity: MEDIUM

CVSS Base Score: 5.5

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 10.08% (scored less or equal to compared to others)

EPSS Date: 2025-06-02 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: none

SSVC Technical Impact: partial

SSVC Automatable: false

References

https://nvd.nist.gov/vuln/detail/CVE-2024-49850
https://git.kernel.org/stable/c/dc7ce14f00bcd50641f2110b7a32aa6552e0780f
https://git.kernel.org/stable/c/2288b54b96dcb55bedebcef3572bb8821fc5e708
https://git.kernel.org/stable/c/584cd3ff792e1edbea20b2a7df55897159b0be3e
https://git.kernel.org/stable/c/e7e9c5b2dda29067332df2a85b0141a92b41f218
https://git.kernel.org/stable/c/3d2786d65aaa954ebd3fcc033ada433e10da21c4

Timeline