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.
CVE-2026-27026
MEDIUMNVD 5.55.5Trending — 3 sources updated this week
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: 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.
- CVSS v3
- 5.5
- EG Score
- 5.5(low)
- 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 computedSeverity55% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 6%
- KEV
- Not listed
Published
February 20, 2026
Last Modified
June 17, 2026
References (4)
- security-advisories@githubhttps://github.com/py-pdf/pypdf/commit/7905842d833f899f1d3228af7e7467ad80277016
- security-advisories@githubhttps://github.com/py-pdf/pypdf/pull/3644
- security-advisories@githubhttps://github.com/py-pdf/pypdf/releases/tag/6.7.1
- security-advisories@githubhttps://github.com/py-pdf/pypdf/security/advisories/GHSA-9mvc-8737-8j8h
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× 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.
- 2026-07-28 15:36 UTCEPSS rescore
- 2026-07-27 14:12 UTCEG score recompute
- 2026-07-27 13:55 UTCOSV refresh
Related CVEs(same CWE)
Same CWE
10 shownCWE-770
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). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
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
Explore the affected products and dependency analysis for CVE-2026-27026
Is Your Infrastructure Affected by CVE-2026-27026?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.