pypdf is a free and open-source pure-python PDF library. Prior to version 6.7.4, an attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the content stream using the RunLengthDecode filter. This has been fixed in pypdf 6.7.4. As a workaround, consider applying the changes from PR #3664.
CVE-2026-28351
MEDIUMNVD 5.35.3
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 5.3 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
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.3
- EG Score
- 5.3(low)
- EG Risk
- 28(Track)EG Risk 28/100SSVC: 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 computedSeverity53% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 35%
- KEV
- Not listed
Published
February 27, 2026
Last Modified
June 17, 2026
References (4)
- security-advisories@githubhttps://github.com/py-pdf/pypdf/commit/f309c6003746414dc7b5048c19e6d879ff2dc858
- security-advisories@githubhttps://github.com/py-pdf/pypdf/pull/3664
- security-advisories@githubhttps://github.com/py-pdf/pypdf/releases/tag/6.7.4
- security-advisories@githubhttps://github.com/py-pdf/pypdf/security/advisories/GHSA-f2v5-7jq9-h8cg
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 2× in last 7d / 2× 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.
- 2026-07-27 14:03 UTCEG score recompute
- 2026-07-27 13:55 UTCOSV refresh
Related CVEs(same CWE)
Same CWE
10 shownCWE-400
Frequently asked(5)
What is CVE-2026-28351?
CVE-2026-28351 is a medium vulnerability published on February 27, 2026. pypdf is a free and open-source pure-python PDF library. Prior to version 6.7.4, an attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the content stream using the RunLengthDecode filter. This has been fixed in pypdf 6.7.4. As a workaround,…
When was CVE-2026-28351 disclosed?
CVE-2026-28351 was first published in the National Vulnerability Database on February 27, 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-2026-28351 actively exploited?
CVE-2026-28351 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 65.3% of all scored CVEs.
What is the CVSS score of CVE-2026-28351?
CVE-2026-28351 has a CVSS v3 base score of 5.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-28351?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-28351, 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-2026-28351
Is Your Infrastructure Affected by CVE-2026-28351?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.