CVE-2026-39376

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 77% 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
Elevated
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

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

FastFeedParser is a high performance RSS, Atom and RDF parser. Prior to 0.5.10, when parse() fetches a URL that returns an HTML page containing a tag, it recursively calls itself with the redirect URL — with no depth limit, no visited-URL deduplication, and no redirect count cap. An attacker-controlled server that returns an infinite chain of HTML meta-refresh responses causes unbounded recursion, exhausting the Python call stack and crashing the process. This vulnerability can also be chained with the companion SSRF issue to reach internal network targets after bypassing the initial URL check. This vulnerability is fixed in 0.5.10.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
24.9%
KEV
Not listed

Published

April 7, 2026

Last Modified

April 14, 2026

Advisory Details (1)

Auto-updated Jun 10, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Infinite redirect loop DoS via meta-refresh chain · Advisory · kagisearch/fastfeedparser · GitHub

https://github.com/kagisearch/fastfeedparser/security/advisories/GHSA-4gx2-pc4f-wq37

Vendor Advisories for CVE-2026-39376(1)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
fastfeedparser0.1.0 ... 0.5.9 (33 versions)0.5.10—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 38× 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. 2026-07-16 17:03 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
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  9. 2026-07-11 08:27 UTCEPSS rescore
  10. 2026-07-09 19:10 UTCEPSS rescore
  11. 2026-07-08 15:15 UTCEPSS rescore
  12. 2026-07-07 13:46 UTCEPSS rescore
  13. 2026-07-06 16:27 UTCEPSS rescore
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  15. 2026-07-06 02:23 UTCEPSS rescore
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  17. 2026-07-05 02:30 UTCEPSS rescore
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  19. 2026-07-01 15:06 UTCEPSS rescore
  20. 2026-06-30 23:22 UTCEPSS rescore
  21. 2026-06-29 14:06 UTCEPSS rescore
  22. 2026-06-28 14:07 UTCEPSS rescore
  23. 2026-06-28 04:56 UTCEPSS rescore
  24. 2026-06-27 03:08 UTCEPSS rescore
  25. 2026-06-25 13:49 UTCEPSS rescore
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  1. 2026-06-25 13:49 UTCEPSS rescore
  2. 2026-06-24 14:05 UTCEPSS rescore
  3. 2026-06-23 21:33 UTCEPSS rescore
  4. 2026-06-22 14:25 UTCEPSS rescore
  5. 2026-06-22 14:25 UTCEPSS rescore
  6. 2026-06-21 14:56 UTCEPSS rescore
  7. 2026-06-21 14:56 UTCEPSS rescore
  8. 2026-06-21 01:59 UTCEPSS rescore
  9. 2026-06-19 19:25 UTCEPSS rescore
  10. 2026-06-19 19:25 UTCEPSS rescore
  11. 2026-06-18 17:52 UTCEPSS rescore
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  13. 2026-06-17 17:53 UTCEPSS rescore
  14. 2026-06-16 17:52 UTCEPSS rescore
  15. 2026-06-15 17:49 UTCEPSS rescore
  16. 2026-06-14 23:18 UTCEPSS rescore
  17. 2026-06-13 23:00 UTCEPSS rescore
  18. 2026-06-12 23:12 UTCEPSS rescore
  19. 2026-06-12 23:12 UTCEPSS rescore
  20. 2026-06-11 14:00 UTCEPSS rescore
  21. 2026-06-10 22:18 UTCEPSS rescore
  22. 2026-06-10 13:22 UTCEPSS rescore
  23. 2026-06-08 14:17 UTCEPSS rescore
  24. 2026-06-08 14:17 UTCEPSS rescore
  25. 2026-06-07 15:25 UTCEPSS rescore
  26. 2026-06-07 15:25 UTCEPSS rescore
  27. 2026-06-07 15:25 UTCEPSS rescore
  28. 2026-06-06 13:47 UTCEPSS rescore
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  30. 2026-06-05 22:47 UTCEPSS rescore
  31. 2026-06-05 22:47 UTCEPSS rescore
  32. 2026-06-05 06:10 UTCEPSS rescore
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  34. 2026-06-04 13:12 UTCEPSS rescore
  35. 2026-06-04 13:12 UTCEPSS rescore
  36. 2026-06-02 20:13 UTCEPSS rescore
  37. 2026-06-01 13:52 UTCEPSS rescore
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  39. 2026-06-01 13:51 UTCEPSS rescore
  40. 2026-05-31 22:30 UTCEPSS rescore
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  42. 2026-05-31 00:16 UTCEPSS rescore
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  45. 2026-05-29 13:44 UTCEPSS rescore
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  47. 2026-05-28 13:44 UTCEPSS rescore
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  49. 2026-05-28 13:44 UTCEPSS rescore
  50. 2026-05-27 13:40 UTCEPSS rescore
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  53. 2026-05-26 13:44 UTCEPSS rescore
  54. 2026-05-26 07:18 UTCEPSS rescore
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  56. 2026-05-20 22:38 UTCEPSS rescore
  57. 2026-05-20 22:38 UTCEPSS rescore
  58. 2026-05-20 18:36 UTCEG score recompute
  59. 2026-05-20 11:22 UTCEPSS rescore
  60. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-39376?
CVE-2026-39376 is a high vulnerability published on April 7, 2026. FastFeedParser is a high performance RSS, Atom and RDF parser. Prior to 0.5.10, when parse() fetches a URL that returns an HTML page containing a <meta http-equiv="refresh"> tag, it recursively calls itself with the redirect URL — with no depth limit, no visited-URL deduplication, and no redirect…
When was CVE-2026-39376 disclosed?
CVE-2026-39376 was first published in the National Vulnerability Database on April 7, 2026, with the most recent update on April 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-39376 actively exploited?
CVE-2026-39376 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 24.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-39376?
CVE-2026-39376 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-39376?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-39376, 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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