CVE-2026-103262 (CVSS 7.5)

Description

Tornado versions before 6.5.9 contain an unbounded memory accumulation vulnerability in CurlAsyncHTTPClient that allows remote attackers to cause denial of service by sending a compressed response. Attackers can send a gzip-encoded decompression bomb that accumulates in memory without size limits, causing the application process to be killed by out-of-memory conditions.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0053

Probability of exploitation

0.43%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-409 CWE-409

References

Other References

https://github.com/tornadoweb/tornado/commit/e412435febba4569c552c5c9054f1bf92bd171a9 https://github.com/tornadoweb/tornado/security/advisories/GHSA-chx6-46f5-w4vp https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-curlasynchttpclient https://github.com/tornadoweb/tornado/security/advisories/GHSA-chx6-46f5-w4vp

Frequently Asked Questions

What is CVE-2026-103262? +

Tornado versions before 6.5.9 contain an unbounded memory accumulation vulnerability in CurlAsyncHTTPClient that allows remote attackers to cause denial of service by sending a compressed response. Attackers can send a gzip-encoded decompression bomb that accumulates in memory without size limits, causing the application process to be killed by out-of-memory conditions. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-103262? +

CVE-2026-103262 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0053, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-103262? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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