pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.
CVE-2026-102997
HIGHPre-NVD 8.78.7—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (20th percentile of EPSS-scored CVEs). 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
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 8.7Exploit: None knownExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 8.7
- EG Score
- 8.7HIGHmedium confidence
- EG Risk
- 39EG Risk 39/100CISA SSVC
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 computedSeverity87% × 45%Exploitation0% × 40%Automatability0% × 15%CISA SSVC: Track at every mission impact level.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 0.3%
- EPSS %ILE
- 20th
- KEV
- Not listed
CISA SSVCTrack at every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
September 30, 2026
Last Modified
October 2, 2026
Advisory Details (4)
Auto-updated Sep 30, 2026Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available
Version 6.18.1, 2026-09-11
Patch available: py-pdf/pypdf 6.18.1
https://github.com/py-pdf/pypdf/releases/tag/6.18.1github_commit Patch Available
commit d9d38cf99b11 (py-pdf/pypdf)
Patch available: py-pdf/pypdf 6.18.1 (contains commit d9d38cf99b11)
https://github.com/py-pdf/pypdf/commit/d9d38cf99b115deb562d3b68f36c33027bc04f79github_pr Patch Available
SEC: Further restrict FlateDecode recovery
Patch available: py-pdf/pypdf 6.18.1 (PR #4073 merged 2026-09-11)
https://github.com/py-pdf/pypdf/pull/4073github Patch Available
Possible long runtimes for partially malformed FlateDecode streams (Follow-up) · Advisory · py-pdf/pypdf · GitHub
https://github.com/py-pdf/pypdf/security/advisories/GHSA-jw7q-gvrg-4vj3Vendor Advisories for CVE-2026-102997(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)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| pypdf | 1.0 ... 6.9.2 (118 versions) | 6.18.1 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 9× 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.
- 2026-10-03 19:15 UTCEG score recompute
- 2026-10-03 14:25 UTCEPSS rescore
- 2026-10-02 17:30 UTCEG score recompute
- 2026-10-02 16:45 UTCEG score recompute
- 2026-10-02 04:27 UTCEG score recompute
- 2026-10-01 19:49 UTCEPSS rescore
- 2026-09-30 21:27 UTCEG score recompute
- 2026-09-30 20:26 UTCEG score recompute
- 2026-09-30 20:25 UTCMITRE cvelistV5first tracked
Related CVEs(same product + same CWE)
Same product
10 shownPyPI:pypdf
Frequently asked(5)
What is CVE-2026-102997?
CVE-2026-102997 is a high vulnerability published on September 30, 2026. pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that…
When was CVE-2026-102997 disclosed?
CVE-2026-102997 was first published on September 30, 2026, with the most recent update on October 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-102997 actively exploited?
CVE-2026-102997 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (20th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-102997?
CVE-2026-102997 has a CVSS base score of 8.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-102997?
A fix for CVE-2026-102997 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-102997 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-102997
Is Your Infrastructure Affected by CVE-2026-102997?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.