CVE-2026-27026

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 94% 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
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: None knownExposed: 0

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

pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malformed /FlateDecode stream, where the byte-by-byte decompression is used. This vulnerability is fixed in 6.7.1.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

February 20, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated Aug 7, 2026
Patch available. Sources: github_commit, github_pr, github_release, github.
github Patch Available

Possible long runtimes for malformed FlateDecode streams · Advisory · py-pdf/pypdf · GitHub

https://github.com/py-pdf/pypdf/security/advisories/GHSA-9mvc-8737-8j8h
github_release Patch Available

Version 6.7.1, 2026-02-17

Patch available: py-pdf/pypdf 6.7.1

https://github.com/py-pdf/pypdf/releases/tag/6.7.1
github_pr Patch Available

SEC: Limit FlateDecode recovery attempts

Patch available: py-pdf/pypdf 6.7.1 (PR #3644 merged 2026-02-17)

https://github.com/py-pdf/pypdf/pull/3644
github_commit Patch Available

commit 7905842d833f (py-pdf/pypdf)

Patch available: py-pdf/pypdf 6.7.1 (contains commit 7905842d833f)

https://github.com/py-pdf/pypdf/commit/7905842d833f899f1d3228af7e7467ad80277016

Affected Packages

(6 across 5 ecosystems)
Debian:12(2)
PackageVulnerable rangeFixed inDependents
pypdf3.17.4-1 ... 6.9.2-2 (14 versions)——
pypdf22.12.1-3, 2.12.1-3+deb12u1, 2.12.1-4——
Debian:11(1)
PackageVulnerable rangeFixed inDependents
pypdf21.26.0-4 ... 2.9.0-1 (24 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
pypdf5.4.0-1, 6.9.0-1, 6.9.2-1, 6.9.2-2——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
pypdf5.4.0-16.9.0-1—
PyPI(1)
PackageVulnerable rangeFixed inDependents
pypdf1.0 ... 6.7.0 (89 versions)6.7.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 26× 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. 2026-09-18 20:06 UTCOSV refresh
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 19:27 UTCEPSS rescore
  4. 2026-09-17 19:30 UTCEPSS rescore
  5. 2026-09-16 14:08 UTCEPSS rescore
  6. 2026-09-16 05:15 UTCEPSS rescore
  7. 2026-09-13 16:47 UTCEPSS rescore
  8. 2026-09-12 15:01 UTCEPSS rescore
  9. 2026-09-11 14:52 UTCEPSS rescore
  10. 2026-09-10 09:34 UTCEPSS rescore
  11. 2026-09-08 22:00 UTCEPSS rescore
  12. 2026-09-07 16:01 UTCEPSS rescore
  13. 2026-09-06 13:47 UTCEPSS rescore
  14. 2026-09-06 13:47 UTCEPSS rescore
  15. 2026-09-04 05:06 UTCEPSS rescore
  16. 2026-09-02 14:11 UTCEPSS rescore
  17. 2026-09-01 13:53 UTCEPSS rescore
  18. 2026-09-01 04:39 UTCEPSS rescore
  19. 2026-08-30 23:03 UTCOSV refresh
  20. 2026-08-30 19:17 UTCEPSS rescore
  21. 2026-08-28 21:41 UTCEPSS rescore
  22. 2026-08-27 14:25 UTCEPSS rescore
  23. 2026-08-26 14:46 UTCEPSS rescore
  24. 2026-08-25 13:48 UTCEPSS rescore
  25. 2026-08-21 23:49 UTCEPSS rescore
Show 31 more
  1. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-19 17:03 UTCEPSS rescore
  3. 2026-08-17 13:47 UTCEPSS rescore
  4. 2026-08-16 14:56 UTCEPSS rescore
  5. 2026-08-16 02:14 UTCEPSS rescore
  6. 2026-08-15 01:30 UTCEPSS rescore
  7. 2026-08-14 09:20 UTCEG score recompute
  8. 2026-08-13 22:00 UTCEPSS rescore
  9. 2026-08-13 01:23 UTCEG score recompute
  10. 2026-08-12 13:50 UTCEPSS rescore
  11. 2026-08-11 13:42 UTCEPSS rescore
  12. 2026-08-11 09:02 UTCEG score recompute
  13. 2026-08-11 00:00 UTCEPSS rescore
  14. 2026-08-10 09:18 UTCEG score recompute
  15. 2026-08-09 13:46 UTCEPSS rescore
  16. 2026-08-09 08:57 UTCEG score recompute
  17. 2026-08-08 16:37 UTCEPSS rescore
  18. 2026-08-07 21:07 UTCEG score recompute
  19. 2026-08-06 13:46 UTCEPSS rescore
  20. 2026-08-06 03:17 UTCEG score recompute
  21. 2026-08-05 19:17 UTCEPSS rescore
  22. 2026-08-04 15:10 UTCEPSS rescore
  23. 2026-08-03 10:36 UTCEPSS rescore
  24. 2026-08-02 19:53 UTCEG score recompute
  25. 2026-08-02 02:26 UTCEPSS rescore
  26. 2026-08-01 04:16 UTCEPSS rescore
  27. 2026-07-30 16:27 UTCEPSS rescore
  28. 2026-07-30 01:30 UTCEPSS rescore
  29. 2026-07-28 15:36 UTCEPSS rescore
  30. 2026-07-27 14:12 UTCEG score recompute
  31. 2026-07-27 13:55 UTCOSV refresh

Frequently asked(5)

What is CVE-2026-27026?
CVE-2026-27026 is a medium vulnerability published on February 20, 2026. pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malformed /FlateDecode stream, where the byte-by-byte decompression is used. This vulnerability is fixed in 6.7.1.
When was CVE-2026-27026 disclosed?
CVE-2026-27026 was first published in the National Vulnerability Database on February 20, 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-2026-27026 actively exploited?
CVE-2026-27026 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 93.5% of all scored CVEs.
What is the CVSS score of CVE-2026-27026?
CVE-2026-27026 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-27026?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-27026, 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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