CVE-2026-81835

MEDIUMPre-NVD 5.55.5—
EchelonGraph scoreHIGH confidence

Score 5.5 from GitHub Security Advisory (severity: LOW) published 2026-08-28. a secondary CVSS source baseline 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this weekElevated
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A security vulnerability has been detected in RooCodeInc Roo-Code up to 3.51.1. This affects the function fetch_instructions of the file malicious_mcp_server.py of the component MCP Integration Trust Model. The manipulation leads to code injection. The attack is possible to be carried out remotely. The exploit has been disclosed publicly and may be used. Multiple isses were reported to the vendor beforehand. They explain, that "they all apply to Roo Code, a project we no longer support - the repository was archived a while ago, and we don't encourage anyone to use it." This vulnerability only affects products that are no longer supported by the maintainer.

CVSS v3
5.5
EG Score
5.5(high)
EG Risk
41(Track)
EG Risk 41/100SSVC: 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 computed
Severity55% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

August 27, 2026

Last Modified

August 28, 2026

Advisory Details (1)

Auto-updated Aug 27, 2026
No patch confirmed yet.
generic

Security Advisory: Roo-Code Untrusted MCP Server Can Inject Arbitrary System Instructions · GitHub

https://gist.github.com/tchen200311/05b5960272c290b7843d6bbdbfe9f7c1

Vendor Advisories for CVE-2026-81835(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 16× in last 7d / 16× 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.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 18:36 UTCEG score recompute
  3. 2026-08-29 18:35 UTCGHSA enrichment
  4. 2026-08-28 21:42 UTCEPSS rescore
  5. 2026-08-28 20:40 UTCEG score recompute
  6. 2026-08-28 20:40 UTCGHSA enrichment
  7. 2026-08-28 20:24 UTCNVD updateCVSS v4 → 2
  8. 2026-08-28 19:46 UTCEG score recompute
  9. 2026-08-28 19:46 UTCGHSA enrichment
  10. 2026-08-28 19:36 UTCMITRE cvelistV5CVSS v4 → 5.1
  11. 2026-08-28 15:18 UTCEG score recompute
  12. 2026-08-28 15:18 UTCGHSA enrichment
  13. 2026-08-28 00:32 UTCEG score recompute
  14. 2026-08-28 00:26 UTCNVD updateCVSS v4 → 2
  15. 2026-08-27 23:23 UTCEG score recompute
  16. 2026-08-27 23:22 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-81835?
CVE-2026-81835 is a medium vulnerability published on August 27, 2026. A security vulnerability has been detected in RooCodeInc Roo-Code up to 3.51.1. This affects the function fetchinstructions of the file maliciousmcp_server.py of the component MCP Integration Trust Model. The manipulation leads to code injection. The attack is possible to be carried out remotely.…
When was CVE-2026-81835 disclosed?
CVE-2026-81835 was first published in the National Vulnerability Database on August 27, 2026, with the most recent update on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81835 actively exploited?
CVE-2026-81835 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 93.4% of all scored CVEs.
What is the CVSS score of CVE-2026-81835?
CVE-2026-81835 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-81835?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81835, 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

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