SB2026091521 - openEuler 24.03 LTS SP3 update for python-tornado

Description

This security bulletin contains information about 3 vulnerabilities.

1) Information disclosure (CVE-ID: CVE-2026-49853)

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote user to disclose credentials intended for one origin to a different origin.

The vulnerability exists due to improper handling of authorization headers in SimpleAsyncHTTPClient when following cross-origin 3xx redirects. A remote user can cause the client to forward authorization credentials to a different origin.

Redirect following is enabled by default.

2) Buffer over-read (CVE-ID: CVE-2026-49854)

CWE-ID: CWE-126 - Buffer over-read

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to a buffer over-read in the tornado.speedups websocket_mask function when processing XSRF tokens. A remote attacker can send a crafted XSRF token with a short mask to disclose sensitive information.

The issue is reachable when xsrf_cookies is enabled and the native extension is active.

3) Improper handling of highly compressed data (CVE-ID: CVE-2026-49855)

CWE-ID: CWE-409 - Improper Handling of Highly Compressed Data (Data Amplification)

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper handling of highly compressed data in Tornado gzip decompression routines when SimpleAsyncHTTPClient processes a response from a malicious server. A remote attacker can provide a compressed response that expands to consume effectively unlimited memory to cause a denial of service.

SimpleAsyncHTTPClient is affected in its default configuration. HTTPServer is affected only when decompress_request=True is set.

Remediation

Install update from vendor's website.

References

• https://www.openeuler.org/en/security/security-bulletins/detail/?id=openEuler-SA-2026-2728