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.
CVE-2026-77650
CRITICALPre-NVD 9.89.8
EchelonGraph scoreLOW confidence
This critical-severity CVE scores 9.8 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: cna:mitre
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 9.8Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.8
- EG Score
- 9.8(low)
- EG Risk
- 49(Track)EG Risk 49/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity98% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
August 21, 2026
Last Modified
August 21, 2026
Advisory Details (5)
Auto-updated Aug 21, 2026No patch confirmed yet.
generic
RUSTSEC-2026-0262: append-only-vec: `append-only-vec` 0.1.9 was removed from crates.io due to a malicious dependency › RustSec Advisory Database
https://rustsec.org/advisories/RUSTSEC-2026-0262.htmlgeneric
Malicious Rust Crate arrayref Runs a Build-Time Payload - Real-time Open Source Software Supply Chain Security
https://safedep.io/arrayref-proc-macro1-rust-build-time-malware/generic
Rust Supply-Chain Attack: arrayref, internment, and append-only-vec Poisoned by the proc-macro1 Build-Time Dropper - StepSecurity
https://www.stepsecurity.io/blog/arrayref-rust-crate-supply-chain-attackgeneric
Malware: `arrayref` 0.3.10 executes a remote payload at build time via typosquatted `proc-macro1` · Issue #3161 · rustsec/advisory-db · GitHub
https://github.com/rustsec/advisory-db/issues/3161generic
Supply chain attack on arrayref | Rust Blog
https://blog.rust-lang.org/2026/08/20/supply-chain-attack-on-arrayrefWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 2× in last 7d / 2× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-21 00:51 UTCEG score recompute
- 2026-08-21 00:51 UTCMITRE cvelistV5first tracked
Frequently asked(4)
What is CVE-2026-77650?
CVE-2026-77650 is a critical vulnerability published on August 21, 2026. 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.
When was CVE-2026-77650 disclosed?
CVE-2026-77650 was first published in the National Vulnerability Database on August 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-77650?
CVE-2026-77650 has a CVSS v4.0 base score of 9.8 (CNA self-assessment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-77650?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77650, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-77650
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