CVE-2026-77650 (CVSS 9.8)

Description

The append-only-vec crate 0.1.9 for Rust can trigger execution of malicious code when compiling a project that uses the crate, because it has a rogue dependency that registers with a command-and-control server to offer arbitrary code execution.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0043

Probability of exploitation

0.37%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-506 CWE-506

References

Other References

https://blog.rust-lang.org/2026/08/20/supply-chain-attack-on-arrayref https://github.com/rustsec/advisory-db/issues/3161 https://rustsec.org/advisories/RUSTSEC-2026-0262.html https://safedep.io/arrayref-proc-macro1-rust-build-time-malware/ https://www.stepsecurity.io/blog/arrayref-rust-crate-supply-chain-attack

Frequently Asked Questions

What is CVE-2026-77650? +

The append-only-vec crate 0.1.9 for Rust can trigger execution of malicious code when compiling a project that uses the crate, because it has a rogue dependency that registers with a command-and-control server to offer arbitrary code execution. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-77650? +

CVE-2026-77650 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0043, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-77650? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-77650