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Fencer Vulns
low 3.3

CVE-2026-50185 json

RustCrypto Cmov/CmovEq on aarch64 can produce wrong results if high-bits of registers are set

published 2026-07-02 4 mo ago modified 2026-10-24 15 d ago also GHSA-3rjw-m598-pq24 , EUVD-2026-45254

cvss
3.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

RustCrypto CMOV provides conditional move CPU intrinsics which are guaranteed on major platforms to execute in constant-time and not be rewritten as branches by the compiler. From 0.1.1 until 0.5.4, the aarch64 implementations of Cmov and CmovEq in cmov/src/backends/aarch64.rs assume high bits are zero-extended when loading values smaller than a register, so set high bits such as [8..] in a Cmov selector or [16..] of self or other in the u16 and i16 CmovEq implementations can cause left.cmovz(&right, condition) to produce incorrect output. This issue is fixed in version 0.5.4.

Patch / fix

  • crates.io cmov 0.5.4
  • rustcrypto cmov 0.5.4
  • rust-cmov Debian 14 0.5.4-1

debian advisories DEBIAN-CVE-2026-50185

  • rust hummingbird 1 1.97.1-1.1.hum1
  • cargo hummingbird 1 1.97.1-1.1.hum1
  • clippy hummingbird 1 1.97.1-1.1.hum1
  • rustfmt hummingbird 1 1.97.1-1.1.hum1
  • rust-gdb hummingbird 1 1.97.1-1.1.hum1
  • rust-src hummingbird 1 1.97.1-1.1.hum1
  • rust-lldb hummingbird 1 1.97.1-1.1.hum1
  • rust-analyzer hummingbird 1 1.97.1-1.1.hum1

red hat advisories RHSA-2026:42923

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-50185 updated cvss 3.3

cmov: cmov: Incorrect output due to improper zero-extension in aarch64 conditional move operations

  • Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9, openshift-sandboxed-containers/osc-podvm-payload-rhel9 Red Hat Enterprise Linux 9 rust, cargo, clippy, rustfmt, rust-gdb, rust-src, +8 more Red Hat Enterprise Linux 10 rust, rust-sequoia-sq Red Hat Trusted Profile Analyzer rhtpa/rhtpa-rhel10, rhtpa/rhtpa-trustification-service-rhel9
    under investigation
  • Red Hat Hardened Images rust 1.97.1-1.1.hum1, cargo 1.97.1-1.1.hum1, clippy 1.97.1-1.1.hum1, rustfmt 1.97.1-1.1.hum1, rust-gdb 1.97.1-1.1.hum1, rust-src 1.97.1-1.1.hum1, +11 more
    fixed: vendor fix RHSA-2026:42923
  • Red Hat Hardened Images netavark 2:2.0.0-1.hum1
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/RustCrypto/utils/security/advisories/GHSA-3rjw-m598-pq24 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 2.0 CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 2.0 CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
crates.io cmov
>=0.1.1, <0.5.4
0.5.4

Affected products

  • RustCrypto utils

Classification

Weakness
  • CWE-758 Reliance on Undefined, Unspecified, or Implementation-Defined Behavior

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.