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Fencer Vulns
medium 5.3

CVE-2026-5223 json

Crates in third party registries can override the cached source of other crates

published 2026-05-25 5 mo ago modified 2026-07-23 3 mo ago also GHSA-jq42-7mfv-hm57 , EUVD-2026-31658

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 22%
public exploits
0
none known

Summary

Cargo incorrectly handled symlinks inside of crate tarballs downloaded from third-party registries, allowing a malicious crate to override the source code of another crate from the same registry. The severity of the vulnerability is **medium** for users of third-party registries. Users of crates.io are **not affected**, as crates.io forbids uploading crates containing any symlink.

Patch / fix

  • crates.io cargo 0.97.0
  • Rust Project Cargo 1.96.0
  • rustc Debian 13 1.85.1+dfsg1-1+deb13u1
  • rustc Debian 14 1.95.0+dfsg1-2
  • rust-cargo Debian 14 0.91.0-3

debian advisories DEBIAN-CVE-2026-5223

  • 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

  • rust Alpine 3.23 1.91.1-r2
  • rust Alpine 3.24 1.96.0-r0
  • chromium-rust Alpine 3.24 1.96.0-r0

alpine advisories ALPINE-CVE-2026-5223

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rust Azure Linux 3.0 1.75.0-30
  • rust Azure Linux 3.0 1.90.0-9

azure linux advisories AZL-88272AZL-88278

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2026-5223 updated cvss 5.3

cargo: Cargo: Source code overwrite due to symlink mishandling in third-party registries

  • Red Hat Enterprise Linux 9 rust, cargo, goose, clippy, rustfmt, rust-gdb, +11 more
    affected: workaround, no fix available “Fix deferred”
  • 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 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
none
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:H/SI:H/SA:H
CNA 4.0 6.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:H/SI:H/SA:H/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 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
crates.io cargo
<0.97.0
0.97.0

Affected products

  • Rust Project Cargo

Classification

Weakness
  • CWE-61 UNIX Symbolic Link (Symlink) Following

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.