CVE-2026-27469

MEDIUMNVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 88% 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
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.1Exploit: None knownExposed: 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)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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
Severity61% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
12%
KEV
Not listed

Published

February 21, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Aug 6, 2026
Patch available. Sources: github, github_commit.
github Patch Available

Stored XSS via comment website field · Advisory · isso-comments/isso · GitHub

https://github.com/isso-comments/isso/security/advisories/GHSA-9fww-8cpr-q66r
github_commit Patch Available

commit 0afbfe0691ee (isso-comments/isso)

Patch available: isso-comments/isso 0.14.0 (contains commit 0afbfe0691ee)

https://github.com/isso-comments/isso/commit/0afbfe0691ee237963e8fb0b2ee01c9e55ca2144
generic

html — HyperText Markup Language support — Python 3.14.7 documentation

https://docs.python.org/3/library/html.html#html.escape

Affected Packages

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 35× 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 159 total refreshes for this CVE.

  1. 2026-08-30 23:03 UTCOSV refresh
  2. 2026-08-30 19:17 UTCEPSS rescore
  3. 2026-08-30 01:22 UTCEPSS rescore
  4. 2026-08-28 21:41 UTCEPSS rescore
  5. 2026-08-27 14:25 UTCEPSS rescore
  6. 2026-08-26 14:46 UTCEPSS rescore
  7. 2026-08-25 13:48 UTCEPSS rescore
  8. 2026-08-23 00:19 UTCEPSS rescore
  9. 2026-08-21 23:49 UTCEPSS rescore
  10. 2026-08-20 22:55 UTCEPSS rescore
  11. 2026-08-19 17:03 UTCEPSS rescore
  12. 2026-08-18 13:48 UTCEPSS rescore
  13. 2026-08-17 13:47 UTCEPSS rescore
  14. 2026-08-16 14:56 UTCEPSS rescore
  15. 2026-08-16 02:14 UTCEPSS rescore
  16. 2026-08-15 01:30 UTCEPSS rescore
  17. 2026-08-14 09:17 UTCEG score recompute
  18. 2026-08-13 22:00 UTCEPSS rescore
  19. 2026-08-13 02:20 UTCEG score recompute
  20. 2026-08-12 13:50 UTCEPSS rescore
  21. 2026-08-12 01:28 UTCEG score recompute
  22. 2026-08-11 13:42 UTCEPSS rescore
  23. 2026-08-11 00:00 UTCEPSS rescore
  24. 2026-08-10 09:46 UTCEG score recompute
  25. 2026-08-09 13:46 UTCEPSS rescore
Show 75 more
  1. 2026-08-09 08:55 UTCEG score recompute
  2. 2026-08-08 16:37 UTCEPSS rescore
  3. 2026-08-07 21:03 UTCEG score recompute
  4. 2026-08-06 13:46 UTCEPSS rescore
  5. 2026-08-06 03:15 UTCEG score recompute
  6. 2026-08-05 19:17 UTCEPSS rescore
  7. 2026-08-04 15:10 UTCEPSS rescore
  8. 2026-08-03 10:36 UTCEPSS rescore
  9. 2026-08-02 19:51 UTCEG score recompute
  10. 2026-08-02 02:26 UTCEPSS rescore
  11. 2026-08-01 04:16 UTCEPSS rescore
  12. 2026-07-30 16:27 UTCEPSS rescore
  13. 2026-07-30 01:30 UTCEPSS rescore
  14. 2026-07-28 15:36 UTCEPSS rescore
  15. 2026-07-26 14:54 UTCEPSS rescore
  16. 2026-07-26 14:54 UTCEPSS rescore
  17. 2026-07-25 14:18 UTCEPSS rescore
  18. 2026-07-25 14:17 UTCEPSS rescore
  19. 2026-07-24 14:17 UTCEPSS rescore
  20. 2026-07-23 14:18 UTCEPSS rescore
  21. 2026-07-23 14:18 UTCEPSS rescore
  22. 2026-07-23 03:08 UTCEG score recompute
  23. 2026-07-22 14:08 UTCEPSS rescore
  24. 2026-07-22 14:08 UTCEPSS rescore
  25. 2026-07-21 15:24 UTCEPSS rescore
  26. 2026-07-21 15:24 UTCEPSS rescore
  27. 2026-07-20 17:08 UTCEPSS rescore
  28. 2026-07-20 17:08 UTCEPSS rescore
  29. 2026-07-19 14:31 UTCEPSS rescore
  30. 2026-07-19 14:31 UTCEPSS rescore
  31. 2026-07-19 02:29 UTCEPSS rescore
  32. 2026-07-18 10:04 UTCEPSS rescore
  33. 2026-07-18 10:04 UTCEPSS rescore
  34. 2026-07-17 11:29 UTCOSV refresh
  35. 2026-07-16 17:03 UTCEPSS rescore
  36. 2026-07-16 17:03 UTCEPSS rescore
  37. 2026-07-15 16:57 UTCEPSS rescore
  38. 2026-07-15 16:57 UTCEPSS rescore
  39. 2026-07-15 02:00 UTCEPSS rescore
  40. 2026-07-15 02:00 UTCEPSS rescore
  41. 2026-07-13 22:30 UTCEPSS rescore
  42. 2026-07-13 06:13 UTCEPSS rescore
  43. 2026-07-13 06:13 UTCEPSS rescore
  44. 2026-07-11 08:27 UTCEPSS rescore
  45. 2026-07-09 19:10 UTCEPSS rescore
  46. 2026-07-08 15:15 UTCEPSS rescore
  47. 2026-07-08 15:15 UTCEPSS rescore
  48. 2026-07-07 13:46 UTCEPSS rescore
  49. 2026-07-06 16:27 UTCEPSS rescore
  50. 2026-07-06 16:27 UTCEPSS rescore
  51. 2026-07-06 02:23 UTCEPSS rescore
  52. 2026-07-06 02:23 UTCEPSS rescore
  53. 2026-07-05 02:30 UTCEPSS rescore
  54. 2026-07-04 06:31 UTCEPSS rescore
  55. 2026-07-04 06:31 UTCEPSS rescore
  56. 2026-07-01 15:06 UTCEPSS rescore
  57. 2026-07-01 15:06 UTCEPSS rescore
  58. 2026-06-29 14:06 UTCEPSS rescore
  59. 2026-06-29 10:02 UTCOSV refresh
  60. 2026-06-28 14:07 UTCEPSS rescore
  61. 2026-06-28 14:07 UTCEPSS rescore
  62. 2026-06-28 04:56 UTCEPSS rescore
  63. 2026-06-28 04:56 UTCEPSS rescore
  64. 2026-06-27 03:08 UTCEPSS rescore
  65. 2026-06-25 13:49 UTCEPSS rescore
  66. 2026-06-25 13:49 UTCEPSS rescore
  67. 2026-06-24 14:05 UTCEPSS rescore
  68. 2026-06-24 14:05 UTCEPSS rescore
  69. 2026-06-23 21:33 UTCEPSS rescore
  70. 2026-06-23 21:32 UTCEPSS rescore
  71. 2026-06-22 14:25 UTCEPSS rescore
  72. 2026-06-22 14:25 UTCEPSS rescore
  73. 2026-06-21 14:56 UTCEPSS rescore
  74. 2026-06-21 14:56 UTCEPSS rescore
  75. 2026-06-21 01:59 UTCEPSS rescore

Related CVEs(same CWE)

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 June 17, 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 0% probability of exploitation in the next 30 days, which ranks it in the top 88.2% of all scored CVEs.
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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-27469

Explore →

Is Your Infrastructure Affected by CVE-2026-27469?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs