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Fencer Intel
low 3.3

CVE-2026-50185 json

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

published 4mo ago modified 18d ago also EUVD-2026-45254 , GHSA-3rjw-m598-pq24

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
  • zeroize_derive_project zeroize_derive 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

Is CVE-2026-50185 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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
3mo ago

Exploit prediction

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

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 Intel 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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.