CVE-2026-82398

MEDIUMPre-NVD 6.96.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, 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, secondary
6.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.9Exploit: 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 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.

CVSS v3
6.9
EG Score
6.9(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: 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
Severity69% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

August 31, 2026

Last Modified

September 9, 2026

Advisory Details (4)

Auto-updated Aug 31, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

Version 6.15.0, 2026-08-06

Patch available: py-pdf/pypdf 6.15.0

https://github.com/py-pdf/pypdf/releases/tag/6.15.0
github_commit Patch Available

commit 4959848e057e (py-pdf/pypdf)

Patch available: py-pdf/pypdf 6.15.0 (contains commit 4959848e057e)

https://github.com/py-pdf/pypdf/commit/4959848e057e37c218dccad7465259210923faaa
github_pr Patch Available

SEC: Improve performance of read_until_whitespace

Patch available: py-pdf/pypdf 6.15.0 (PR #3947 merged 2026-08-06)

https://github.com/py-pdf/pypdf/pull/3947
github Patch Available

Inefficient handling of non-whitespace inputs in read_until_whitespace · Advisory · py-pdf/pypdf · GitHub

https://github.com/py-pdf/pypdf/security/advisories/GHSA-fc8x-2rww-xw9m

Vendor Advisories for CVE-2026-82398(1)

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

Affected Packages

(5 across 4 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: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
pypdf5.4.0-1, 6.9.0-1, 6.9.2-1, 6.9.2-2——
PyPI(1)
PackageVulnerable rangeFixed inDependents
pypdf1.0 ... 6.9.2 (112 versions)6.15.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 29× 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 19:28 UTCEPSS rescore
  2. 2026-09-18 16:17 UTCEG score recompute
  3. 2026-09-16 16:05 UTCEG score recompute
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-15 16:12 UTCEG score recompute
  7. 2026-09-15 03:12 UTCEPSS rescore
  8. 2026-09-15 03:12 UTCEPSS rescore
  9. 2026-09-14 16:19 UTCEG score recompute
  10. 2026-09-12 16:33 UTCEG score recompute
  11. 2026-09-11 16:40 UTCEG score recompute
  12. 2026-09-11 14:53 UTCEPSS rescore
  13. 2026-09-11 14:53 UTCEPSS rescore
  14. 2026-09-10 16:47 UTCEG score recompute
  15. 2026-09-08 23:28 UTCEG score recompute
  16. 2026-09-08 22:01 UTCEPSS rescore
  17. 2026-09-06 15:14 UTCEG score recompute
  18. 2026-09-06 13:48 UTCEPSS rescore
  19. 2026-09-05 15:31 UTCEPSS rescore
  20. 2026-09-04 15:27 UTCEG score recompute
  21. 2026-09-04 05:07 UTCEPSS rescore
  22. 2026-09-02 15:35 UTCEG score recompute
  23. 2026-09-02 14:12 UTCEPSS rescore
  24. 2026-09-01 15:40 UTCEG score recompute
  25. 2026-09-01 15:04 UTCEG score recompute
Show 4 more
  1. 2026-09-01 13:54 UTCEPSS rescore
  2. 2026-08-31 22:21 UTCEG score recompute
  3. 2026-08-31 21:45 UTCEG score recompute
  4. 2026-08-31 21:44 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-82398?
CVE-2026-82398 is a medium vulnerability published on August 31, 2026. pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/utils.py function readuntil_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes…
When was CVE-2026-82398 disclosed?
CVE-2026-82398 was first published in the National Vulnerability Database on August 31, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-82398 actively exploited?
CVE-2026-82398 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 77.0% of all scored CVEs.
What is the CVSS score of CVE-2026-82398?
CVE-2026-82398 has a CVSS v3 base score of 6.9 (NVD).
How do I remediate CVE-2026-82398?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-82398, 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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