CVE-2026-54275

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 82% 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, nvd
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

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

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, the server_hostname TLS SNI check can be bypassed when an existing connection is reused. If an application makes multiple requests to the same domain, but with different per-request server_hostname parameters, then the later calls may succeed by reusing the existing connection when they should have been rejected due to the TLS SNI check. This vulnerability is fixed in 3.14.1.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
18.0%
KEV
Not listed

Published

June 15, 2026

Last Modified

June 26, 2026

Advisory Details (1)

Auto-updated Jun 26, 2026
Patch available. Sources: github.
github Patch Available

TLS Server Hostname Override Is Ignored When Reusing HTTPS Connections · Advisory · aio-libs/aiohttp · GitHub

https://github.com/aio-libs/aiohttp/security/advisories/GHSA-4m7w-qmgq-4wj5

Vendor Advisories for CVE-2026-54275(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
aiohttp0.1 ... 3.9.5 (307 versions)3.14.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 22× in last 7d / 39× 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. 2026-07-07 00:17 UTCEG score recompute
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-06 01:12 UTCEG score recompute
  7. 2026-07-05 12:04 UTCEG score recompute
  8. 2026-07-05 02:31 UTCEPSS rescore
  9. 2026-07-05 02:30 UTCEPSS rescore
  10. 2026-07-04 23:01 UTCEG score recompute
  11. 2026-07-04 09:59 UTCEG score recompute
  12. 2026-07-04 06:31 UTCEPSS rescore
  13. 2026-07-04 06:31 UTCEPSS rescore
  14. 2026-07-03 20:17 UTCEG score recompute
  15. 2026-07-03 07:16 UTCEG score recompute
  16. 2026-07-02 17:20 UTCEG score recompute
  17. 2026-07-02 04:02 UTCEG score recompute
  18. 2026-07-01 15:07 UTCEPSS rescore
  19. 2026-07-01 15:01 UTCEG score recompute
  20. 2026-07-01 01:59 UTCEG score recompute
  21. 2026-06-30 23:22 UTCEPSS rescore
  22. 2026-06-30 12:57 UTCEG score recompute
  23. 2026-06-29 22:48 UTCEG score recompute
  24. 2026-06-29 14:06 UTCEPSS rescore
  25. 2026-06-29 14:06 UTCEPSS rescore
Show 14 more
  1. 2026-06-29 09:46 UTCEG score recompute▲ 4.80
  2. 2026-06-28 14:07 UTCEPSS rescore
  3. 2026-06-28 04:56 UTCEPSS rescore
  4. 2026-06-28 04:56 UTCEPSS rescore
  5. 2026-06-27 03:08 UTCEPSS rescore
  6. 2026-06-26 19:41 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  7. 2026-06-26 02:44 UTCEG score recompute
  8. 2026-06-25 13:49 UTCEPSS rescore
  9. 2026-06-24 14:05 UTCEPSS rescore
  10. 2026-06-23 21:33 UTCEPSS rescore
  11. 2026-06-23 21:33 UTCEPSS rescore
  12. 2026-06-22 19:42 UTCEG score recompute▲ 2.70
  13. 2026-06-22 19:40 UTCNVD updateCVSS v3 → 2.7 · CVSS v4 → 2.7
  14. 2026-06-15 20:47 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-54275?
CVE-2026-54275 is a high vulnerability published on June 15, 2026. AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, the serverhostname TLS SNI check can be bypassed when an existing connection is reused. If an application makes multiple requests to the same domain, but with different per-request serverhostname…
When was CVE-2026-54275 disclosed?
CVE-2026-54275 was first published in the National Vulnerability Database on June 15, 2026, with the most recent update on June 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54275 actively exploited?
CVE-2026-54275 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 18.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-54275?
CVE-2026-54275 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-54275?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54275, 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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