How severe is CVE-2026-34515?

CVE-2026-34515 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-34515 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34515?

CVE-2026-34515 affects Aiohttp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34515?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-34515 have an EU (EUVD) identifier?

Yes. CVE-2026-34515 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18039.

When was CVE-2026-34515 published?

CVE-2026-34515 was published on 2026-04-01 and last updated on 2026-06-17.

CVE-2026-34515

CVE-2026-34515 is a high-severity vulnerability in Aiohttp with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-36.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 6.6
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18039
Weakness: CWE-36
Affected product: Aiohttp
Published: 2026-04-01
Last modified: 2026-06-17

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, on Windows the static resource handler may expose information about a NTLMv2 remote path. This issue has been patched in version 3.13.4.

Frequently asked questions

What is CVE-2026-34515?: AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, on Windows the static resource handler may expose information about a NTLMv2 remote path. This issue has been patched in version 3.13.4.
How severe is CVE-2026-34515?: CVE-2026-34515 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-34515 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34515?: CVE-2026-34515 affects Aiohttp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34515?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-34515 have an EU (EUVD) identifier?: Yes. CVE-2026-34515 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18039.
When was CVE-2026-34515 published?: CVE-2026-34515 was published on 2026-04-01 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:aiohttp:aiohttp:*:*:*:*:*:*:*:*

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