Look up another CVE · open CVE-2026-64311 in the interactive tracker
CVE-2026-64311
crypto: loongson - Remove broken and unused loongson-rng
Published 2026-07-25 (3 months ago) by the Linux kernel CNA. Subsystem MAINTAINERS. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-64311 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 | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The loongson-rng rng_alg has several vulnerabilities, including not providing forward security, and a use-after-free bug due to the use of wait_for_completion_interruptible(). Meanwhile, the rng_alg framework doesn't really have any purpose in the first place other than to access the software algorithms crypto/drbg.c and crypto/jitterentropy.c. Hardware-specific rng_algs have no in-kernel user, and unlike hwrng there's no feed into the actual Linux RNG. As such, there's really no point to this code. There are of course other rng_alg drivers that are similarly unused, but they're similarly in the process of being phased out, e.g. https://lore.kernel.org/r/20260529193648.18172-1-ebiggers@kernel.org and https://lore.kernel.org/r/20260529220430.34135-1-ebiggers@kernel.org Given that, there's no point in fixing forward these vulnerabilities, and it makes much more sense to simply roll back the addition of this driver. If this platform provides TRNG (not PRNG) functionality, it could make sense to add a hwrng driver, but it would be quite different.
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.
MAINTAINERS
arch/loongarch/configs/loongson32_defconfig
arch/loongarch/configs/loongson64_defconfig
drivers/crypto/Kconfig
drivers/crypto/Makefile
drivers/crypto/loongson/Kconfig
drivers/crypto/loongson/Makefile
drivers/crypto/loongson/loongson-rng.c
- What this is
- LOONGARCHMAINTAINERS section matched on arch/loongarch/ · loongarch@lists.linux.dev · Maintained
Show whether Debian builds this, per release
Not established. This site could not find the build rule for the affected file in the kernel trees Debian ships, so it has no answer about whether Debian compiles this code. Read that as unknown, never as absent.
- bookworm, trixie, forky, sid?
- ?
- not established - no Makefile entry for the affected file
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
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
Signals
- Published
- 2026-07-25 (3 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.17%, higher than 5.8% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- MAINTAINERS
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.18 | 6.18.39 | 037ec8353711 |
| 6.18 | 7.1.4 | 43de8b9f01b7 |
| 6.18 | 7.2 | af3d1bb9a09d |
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
- An attacker reaches the vulnerable driver through local AF_ALG socket operations selecting the "rng" type and "loongson_stdrng" algorithm. No network or physical-device input path invokes it.
- AC:LAttack complexity, low
- The attacker can repeatedly issue RNG requests and interrupt the waiting thread with signals, causing the asynchronous operation to outlive the interrupted call. Both request initiation and interruption are attacker-controlled.
- PR:LPrivileges required, low
- AF_ALG RNG creation, binding, acceptance, and generation require only an unprivileged local account and contain no capability check. The CAP_SYS_ADMIN check applies only to the separate CAVP entropy-testing operation.
- UI:NUser interaction, none
- The attacker can open and operate the AF_ALG sockets and deliver the signal without any action by another user.
- S:UScope, unchanged
- Exploitation compromises the host kernel within the same security authority; this is ordinary local privilege escalation rather than a VM, IOMMU, or other scope-boundary escape.
- C:HConfidentiality impact, high
- The documented use-after-free can permit attacker-controlled memory reuse and disclosure of arbitrary kernel or process-sensitive memory.
- I:HIntegrity impact, high
- The use-after-free and outstanding asynchronous engine operation constitute exploitable memory corruption that can potentially provide arbitrary writes or kernel control-flow hijacking.
- A:HAvailability impact, high
- Use-after-free access or corruption during asynchronous completion can cause a kernel oops, panic, or complete system crash.