CVE-2026-59197

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 66% 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
Elevated
8.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.2Exploit: NoneExposed: 0

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

Pillow is a Python imaging library. Prior to 12.3.0, Pillow's public rank-filter API can trigger a native heap out-of-bounds write when given a very large odd filter size because ImageFilter.RankFilter.filter() calls image.expand(size // 2, size // 2) before rank-filter size validation and ImagingExpand() computes output dimensions with unchecked signed int arithmetic. This issue is fixed in version 12.3.0.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
68(Attend)
EG Risk 68/100SSVC: Attend

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
Severity82% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS
33.7%
KEV
Not listed

Published

July 14, 2026

Last Modified

July 21, 2026

Advisory Details (4)

Auto-updated Jul 14, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_pr, github_release, github.
github Patch Available🟡 PoC Available

Heap out-of-bounds write in Pillow `ImageFilter.RankFilter` via integer overflow in `ImagingExpand` · Advisory · python-pillow/Pillow · GitHub

https://github.com/python-pillow/Pillow/security/advisories/GHSA-xj96-63gp-2gmr
github_release Patch Available

12.3.0

Patch available: python-pillow/Pillow 12.3.0

https://github.com/python-pillow/Pillow/releases/tag/12.3.0
github_pr Patch Available

Validate large filter sizes when initializing RankFilter

Patch available: python-pillow/Pillow 12.3.0 (PR #9695 merged 2026-06-21)

https://github.com/python-pillow/Pillow/pull/9695
github_commit Patch Available

commit cce3bdb867c7 (python-pillow/Pillow)

Patch available: python-pillow/Pillow 12.3.0 (contains commit cce3bdb867c7)

https://github.com/python-pillow/Pillow/commit/cce3bdb867c77a3420261ed1bfdb6b0787ec8fc1

Vendor Advisories for CVE-2026-59197(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)
PackageVulnerable rangeFixed inDependents
pillow1.0 ... 9.5.0 (106 versions)12.3.0—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 14× 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. 2026-07-23 03:21 UTCEG score recompute
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-22 14:08 UTCEPSS rescore
  4. 2026-07-21 15:25 UTCEPSS rescore
  5. 2026-07-21 15:25 UTCEPSS rescore
  6. 2026-07-20 17:08 UTCEPSS rescore
  7. 2026-07-19 14:31 UTCEPSS rescore
  8. 2026-07-19 02:29 UTCEPSS rescore
  9. 2026-07-18 10:04 UTCEPSS rescore
  10. 2026-07-16 17:03 UTCEPSS rescore
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-15 16:57 UTCEPSS rescore
  13. 2026-07-14 16:40 UTCEG score recompute
  14. 2026-07-14 16:40 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-59197?
CVE-2026-59197 is a high vulnerability published on July 14, 2026. Pillow is a Python imaging library. Prior to 12.3.0, Pillow's public rank-filter API can trigger a native heap out-of-bounds write when given a very large odd filter size because ImageFilter.RankFilter.filter() calls image.expand(size // 2, size // 2) before rank-filter size validation and…
When was CVE-2026-59197 disclosed?
CVE-2026-59197 was first published in the National Vulnerability Database on July 14, 2026, with the most recent update on July 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59197 actively exploited?
CVE-2026-59197 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 33.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-59197?
CVE-2026-59197 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-59197?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59197, 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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