CVE-2026-77972

CRITICALPre-NVD 9.09.0—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 75% 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
Trending — 4 sources updated this week
9.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.0Exploit: None knownExposed: 0

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

Time-of-check Time-of-use (TOCTOU) Race Condition in Slab safeurl allows an attacker who controls a hostname's DNS responses to reach internal network destinations that validation rejected.

Validation returns a verdict and not the address it approved, so the HTTP clients the library ships receive the original hostname and resolve it a second time when the request is made. An attacker who controls the authoritative DNS for a name can answer the first lookup with a permitted address and the second with a blocked one, and the request then reaches a destination validation never approved. The same window opens without an attacker whenever a name legitimately resolves to different addresses across lookups, such as short record lifetimes or rotation between several addresses.

This issue affects safeurl: from 0.1.0 onward.

CVSS v3
9.0
EG Score
9.0(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity90% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
25%
KEV
Not listed

Published

September 15, 2026

Last Modified

September 16, 2026

Advisory Details (3)

Auto-updated Sep 15, 2026
Patch available. Sources: github_commit.
github_commit Patch Available

commit feabbd0a13f8 (slab/safeurl-elixir)

Patch available: slab/safeurl-elixir v0.2.0 (contains commit feabbd0a13f8)

https://github.com/slab/safeurl-elixir/commit/feabbd0a13f83028ab24b71710526e9da9841f70
generic

OSV - Open Source Vulnerabilities

https://osv.dev/vulnerability/EEF-CVE-2026-77972
generic

CVE-2026-77972

https://cna.erlef.org/cves/CVE-2026-77972.html

Vendor Advisories for CVE-2026-77972(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 34× in last 7d / 34× 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. 2026-09-19 23:08 UTCGHSA enrichment
  2. 2026-09-19 19:13 UTCEG score recompute
  3. 2026-09-19 19:13 UTCGHSA enrichment
  4. 2026-09-19 15:08 UTCGHSA enrichment
  5. 2026-09-19 11:12 UTCGHSA enrichment
  6. 2026-09-19 07:18 UTCGHSA enrichment
  7. 2026-09-19 03:22 UTCGHSA enrichment
  8. 2026-09-18 23:26 UTCGHSA enrichment
  9. 2026-09-18 19:31 UTCEG score recompute
  10. 2026-09-18 19:31 UTCGHSA enrichment
  11. 2026-09-18 19:28 UTCEPSS rescore
  12. 2026-09-18 15:34 UTCGHSA enrichment
  13. 2026-09-18 11:36 UTCGHSA enrichment
  14. 2026-09-18 07:39 UTCGHSA enrichment
  15. 2026-09-18 03:44 UTCGHSA enrichment
  16. 2026-09-17 23:49 UTCEG score recompute
  17. 2026-09-17 23:49 UTCGHSA enrichment
  18. 2026-09-17 19:22 UTCGHSA enrichment
  19. 2026-09-17 12:57 UTCGHSA enrichment
  20. 2026-09-17 08:53 UTCGHSA enrichment
  21. 2026-09-17 04:57 UTCGHSA enrichment
  22. 2026-09-17 01:02 UTCGHSA enrichment
  23. 2026-09-16 21:07 UTCGHSA enrichment
  24. 2026-09-16 17:55 UTCEG score recompute
  25. 2026-09-16 17:55 UTCGHSA enrichment
Show 9 more
  1. 2026-09-16 14:08 UTCEPSS rescore
  2. 2026-09-16 12:43 UTCGHSA enrichment
  3. 2026-09-16 08:48 UTCGHSA enrichment
  4. 2026-09-16 04:37 UTCGHSA enrichment
  5. 2026-09-16 00:42 UTCGHSA enrichment
  6. 2026-09-15 20:47 UTCGHSA enrichment
  7. 2026-09-15 16:32 UTCEG score recompute
  8. 2026-09-15 15:43 UTCEG score recompute
  9. 2026-09-15 15:42 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-77972?
CVE-2026-77972 is a critical vulnerability published on September 15, 2026. Time-of-check Time-of-use (TOCTOU) Race Condition in Slab safeurl allows an attacker who controls a hostname's DNS responses to reach internal network destinations that validation rejected. Validation returns a verdict and not the address it approved, so the HTTP clients the library ships receive…
When was CVE-2026-77972 disclosed?
CVE-2026-77972 was first published in the National Vulnerability Database on September 15, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77972 actively exploited?
CVE-2026-77972 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 75.2% of all scored CVEs.
What is the CVSS score of CVE-2026-77972?
CVE-2026-77972 has a CVSS v3 base score of 9.0 (NVD).
How do I remediate CVE-2026-77972?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77972, 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-2026-77972

Explore →

Is Your Infrastructure Affected by CVE-2026-77972?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs