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CVE-2026-80675
libbpf: Reject non-exclusive metadata maps in the signed loader
Published 2026-08-28 (2 months ago) by the Linux kernel CNA. Subsystem include/linux. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-80675 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The loader verifies map->sha against the metadata hash in its instructions. map->sha is calculated when BPF_OBJ_GET_INFO_BY_FD is called on the frozen map. While the map is frozen, the /signed loader/ must also ensure the map is exclusive, as, without exclusivity (which a hostile host could just omit when loading the loader), another BPF program with map access can mutate the contents afterwards, so the check passes on stale data. With the extra check as part of the signed loader, it now refuses to move on with map->sha validation if the host set it up wrongly.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
include/linux/bpf.h
kernel/bpf/syscall.c
tools/lib/bpf/gen_loader.c
- What this is
- BPF [CORE]MAINTAINERS section matched on include/linux/bpf* · bpf@vger.kernel.org · Maintained
Check it on the machine
grep -wE 'CONFIG_BPF|CONFIG_BPF_SYSCALL' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
Show whether Debian builds this, per release
Debian builds this code. Every release below compiles the affected file into the kernels it ships.
- bookworm, trixie, forky, sidy
- y
- built into the kernel image on every flavour - only a patch removes it
- Build switches
- CONFIG_BPF, CONFIG_BPF_SYSCALL
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-28 (2 months ago)source
- CVSS
- 7.1 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Nsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.17%, higher than 5.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- include/linux
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.18 | 6.18.40 | b6862b6a25c6 |
| 6.18 | 7.1.5 | 0dad5adeb34b |
| 6.18 | 7.2 | 0fb6c9ed6493 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The flaw is reached only through bpf(2) syscalls (BPF_MAP_CREATE, BPF_MAP_FREEZE, BPF_OBJ_GET_INFO_BY_FD, BPF_PROG_LOAD, BPF_PROG_RUN) and BPF map helpers on the metadata map; per kernel guidance BPF is a local attack vector.
- AC:LAttack complexity, low
- Exploitation is a reliable attacker-controlled sequence: omit excl_prog_hash, freeze and hash benign metadata, mutate the map via a colluding BPF program, then run the signed loader with no races or uncontrollable layout dependencies.
- PR:LPrivileges required, low
- Triggering the signed-loader path requires local BPF privileges (CAP_BPF for map/program operations); per kernel guidance this is Low because CAP_BPF can be obtained by unprivileged users via user namespaces and BPF tokens, not only init-namespace root.
- UI:NUser interaction, none
- No victim interaction is required; a hostile host or local attacker with BPF access can omit map exclusivity, tamper metadata between hash computation and loader execution, and bypass verification without actions by other users.
- S:UScope, unchanged
- The impact is bypass of BPF signed-loader metadata integrity controls within the kernel BPF subsystem, enabling load of attacker-controlled programs; this is standard kernel security-boundary impact, not VM escape or IOMMU bypass.
- C:HConfidentiality impact, high
- Bypassing metadata verification lets a tampered signed loader instantiate arbitrary BPF programs that can use kernel helpers such as bpf_probe_read_kernel for arbitrary kernel memory disclosure, not merely a bounded leak.
- I:HIntegrity impact, high
- Without the exclusivity check, cached map->sha can remain valid while another BPF program rewrites frozen metadata, letting the loader execute a tampered blob and load unsigned or attacker-chosen BPF with kernel write and code-execution potential.
- A:NAvailability impact, none
- This is an authentication and integrity bypass without memory corruption, use-after-free, or kernel panic; exploitation does not inherently cause crashes, hangs, or denial of kernel availability.