CVE-2026-27469

MEDIUMNVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 71% of all CVEs by exploit prediction. 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: epss, nvd
6.1
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.1Exploit: NoneExposed: 0

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

Isso is a lightweight commenting server written in Python and JavaScript. In commits before 0afbfe0691ee237963e8fb0b2ee01c9e55ca2144, there is a stored Cross-Site Scripting (XSS) vulnerability affecting the website and author comment fields. The website field was HTML-escaped using quote=False, which left single and double quotes unescaped. Since the frontend inserts the website value directly into a single-quoted href attribute via string concatenation, a single quote in the URL breaks out of the attribute context, allowing injection of arbitrary event handlers (e.g. onmouseover, onclick). The same escaping is missing entirely from the user-facing comment edit endpoint (PUT /id/) and the moderation edit endpoint (POST /id//edit/). This issue has been patched in commit 0afbfe0691ee237963e8fb0b2ee01c9e55ca2144. To workaround, nabling comment moderation (moderation = enabled = true in isso.cfg) prevents unauthenticated users from publishing comments, raising the bar for exploitation, but it does not fully mitigate the issue since a moderator activating a malicious comment would still expose visitors.

CVSS v3
6.1
EG Score
6.1(medium)
EPSS
12.0%
KEV
Not listed

Published

February 21, 2026

Last Modified

April 15, 2026

References (3)

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
isso0.10 ... 0.9.9 (34 versions)0.13.2—

Data Freshness Timeline

(refreshed 11× in last 7d / 48× 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.

Showing the most recent 100 of 101 total refreshes for this CVE.

  1. 2026-07-17 11:29 UTCOSV refresh
  2. 2026-07-16 17:03 UTCEPSS rescore
  3. 2026-07-16 17:03 UTCEPSS rescore
  4. 2026-07-15 16:57 UTCEPSS rescore
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  25. 2026-06-29 14:06 UTCEPSS rescore
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  1. 2026-06-29 10:02 UTCOSV refresh
  2. 2026-06-28 14:07 UTCEPSS rescore
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  21. 2026-06-18 17:52 UTCEPSS rescore
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  24. 2026-06-16 17:52 UTCEPSS rescore
  25. 2026-06-15 17:48 UTCEPSS rescore
  26. 2026-06-14 23:18 UTCEPSS rescore
  27. 2026-06-13 23:00 UTCEPSS rescore
  28. 2026-06-12 23:12 UTCEPSS rescore
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  31. 2026-06-10 22:18 UTCEPSS rescore
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  45. 2026-06-04 13:12 UTCEPSS rescore
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  47. 2026-06-02 20:13 UTCEPSS rescore
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  49. 2026-06-01 13:51 UTCEPSS rescore
  50. 2026-06-01 13:51 UTCEPSS rescore
  51. 2026-06-01 12:24 UTCOSV refresh
  52. 2026-05-31 22:30 UTCEPSS rescore
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  54. 2026-05-31 00:16 UTCEPSS rescore
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  56. 2026-05-29 13:44 UTCEPSS rescore
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  69. 2026-05-24 16:59 UTCEPSS rescore
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  71. 2026-05-22 21:16 UTCEPSS rescore
  72. 2026-05-20 22:38 UTCEPSS rescore
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  74. 2026-05-20 22:37 UTCEPSS rescore
  75. 2026-05-20 22:19 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-27469?
CVE-2026-27469 is a medium vulnerability published on February 21, 2026. Isso is a lightweight commenting server written in Python and JavaScript. In commits before 0afbfe0691ee237963e8fb0b2ee01c9e55ca2144, there is a stored Cross-Site Scripting (XSS) vulnerability affecting the website and author comment fields. The website field was HTML-escaped using quote=False,…
When was CVE-2026-27469 disclosed?
CVE-2026-27469 was first published in the National Vulnerability Database on February 21, 2026, with the most recent update on April 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-27469 actively exploited?
CVE-2026-27469 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 12.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-27469?
CVE-2026-27469 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-27469?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-27469, 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.

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