python3 security update (CVE-2026-15806)
Python combines remarkable power with very clear syntax. It has modules, classes, exceptions, very high level dynamic data types, and dynamic typing. There are interfaces to many system calls and libraries, as well as to various windowing systems. New built-in modules are easily written in C or C++ (or other languages, depending on the chosen implementation). Python is also usable as an extension language for applications written in other languages that need easy-to-use scripting or automation interfaces. Security Fix(es): The HTTPPasswordMgr class in the urllib.request module, along with its subclasses HTTPPasswordMgrWithDefaultRealm and HTTPPasswordMgrWithPriorAuth, did not take the URL scheme into account when matching stored credentials against a requested URL. Credentials added for an https:// URL were also used for requests to the same host over http://, so an attacker able to redirect or downgrade a client to plain HTTP (for example, via an HTTPS-to-HTTP redirect or an on-path position) could capture credentials in cleartext. Credentials added for http:// URLs could likewise be sent over https://. Credential matching is now scoped by URL scheme. Credentials registered with a URL that includes a scheme are only used for requests with the same scheme. Credentials registered with a bare authority (such as example.com or example.com:8080) continue to match any scheme, preserving compatibility with existing code, including proxy authentication.(CVE-2026-15806) The "stringprep" module didn't process characters from RFC 3454 tables B.2 or B.3 correctly: the latest Unicode codepoint attributes were used instead of the specified Unicode 3.2.0. This behavior would cause mismatches when processing domain names using IDNA 2003 (the "idna" codec) and the in_table_b2() function of the "stringprep" module. This only affects domain names containing characters that were not previously registered or had their Unicode attributes such as case-folding behavior updated since Unicode 3.2.0.(CVE-2026-17084) Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().(CVE-2026-18503) The tarfile module's tar and data extraction filters created directories outside the destination for members whose name leaves the destination and returns to it, such as ../evil/../dest/sub/file. The containment check used the resolved path, but intermediate directories were created from the name as given. Only empty directories are created outside the destination. Member contents are still extracted inside it. To return to the destination the member's name must contain the destination directory's own final component, so extraction into a secure randomised directory is not affected. This affects POSIX platforms only. On Windows, .. components are collapsed before the path reaches the filesystem, so the directories outside the destination are never created.(CVE-2026-19672) In CPython 3.13 and earlier, the tarfile module's data and tar extraction filters are vulnerable to crafted archives containing a hard link to a symbolic link. Such archives may cause extraction to modify the permissions or modification time of a file outside the destination directory, or expose the contents of that file within the extracted tree.(CVE-2026-82049) When tarfile extracts a link on a system that doesn't support links, it falls back to extracting a member from the archive. In this case, the filter function is run twice: once for the extracted member, and once with name set to the location of the link. For one of the calls, the return value was ignored. Instead, the member should be skipped if either call returns None.(CVE-2026-87910)
AI Analysis
Technical Summary
The urllib.request module's HTTPPasswordMgr classes did not consider URL schemes when matching credentials, allowing credentials for HTTPS URLs to be sent over HTTP and vice versa, risking credential exposure via downgrade or redirect attacks (CVE-2026-15806). The stringprep module incorrectly processed certain Unicode characters, causing mismatches in domain name processing with IDNA 2003 (CVE-2026-17084). The csv.Sniffer.sniff() method can be exploited with crafted CSV input to cause super-linear regex processing and high CPU usage (CVE-2026-18503). The tarfile module's extraction filters could create directories outside the intended destination on POSIX systems due to improper path handling (CVE-2026-19672), and crafted archives with hard links to symbolic links could modify files outside the extraction directory or expose their contents (CVE-2026-82049). Additionally, tarfile extraction filters mishandled fallback extraction on systems without link support, potentially skipping necessary checks (CVE-2026-87910).
Potential Impact
These vulnerabilities can lead to credential exposure through improper credential reuse across HTTP and HTTPS schemes, denial of service via CPU exhaustion, incorrect domain name processing affecting applications relying on stringprep, and potential unauthorized file system modifications or information disclosure during archive extraction. The impact ranges from credential compromise to resource exhaustion and file system integrity issues.
Mitigation Recommendations
An official patch is available addressing these vulnerabilities. Users should upgrade to Python versions at or beyond 3.11.6-45.oe2403sp4 or the corresponding patched releases. Applying these updates will mitigate the credential exposure, CPU exhaustion, Unicode processing, and tarfile extraction vulnerabilities. No additional mitigation actions are required beyond applying the official fixes.
python3 security update (CVE-2026-15806)
Description
Python combines remarkable power with very clear syntax. It has modules, classes, exceptions, very high level dynamic data types, and dynamic typing. There are interfaces to many system calls and libraries, as well as to various windowing systems. New built-in modules are easily written in C or C++ (or other languages, depending on the chosen implementation). Python is also usable as an extension language for applications written in other languages that need easy-to-use scripting or automation interfaces. Security Fix(es): The HTTPPasswordMgr class in the urllib.request module, along with its subclasses HTTPPasswordMgrWithDefaultRealm and HTTPPasswordMgrWithPriorAuth, did not take the URL scheme into account when matching stored credentials against a requested URL. Credentials added for an https:// URL were also used for requests to the same host over http://, so an attacker able to redirect or downgrade a client to plain HTTP (for example, via an HTTPS-to-HTTP redirect or an on-path position) could capture credentials in cleartext. Credentials added for http:// URLs could likewise be sent over https://. Credential matching is now scoped by URL scheme. Credentials registered with a URL that includes a scheme are only used for requests with the same scheme. Credentials registered with a bare authority (such as example.com or example.com:8080) continue to match any scheme, preserving compatibility with existing code, including proxy authentication.(CVE-2026-15806) The "stringprep" module didn't process characters from RFC 3454 tables B.2 or B.3 correctly: the latest Unicode codepoint attributes were used instead of the specified Unicode 3.2.0. This behavior would cause mismatches when processing domain names using IDNA 2003 (the "idna" codec) and the in_table_b2() function of the "stringprep" module. This only affects domain names containing characters that were not previously registered or had their Unicode attributes such as case-folding behavior updated since Unicode 3.2.0.(CVE-2026-17084) Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().(CVE-2026-18503) The tarfile module's tar and data extraction filters created directories outside the destination for members whose name leaves the destination and returns to it, such as ../evil/../dest/sub/file. The containment check used the resolved path, but intermediate directories were created from the name as given. Only empty directories are created outside the destination. Member contents are still extracted inside it. To return to the destination the member's name must contain the destination directory's own final component, so extraction into a secure randomised directory is not affected. This affects POSIX platforms only. On Windows, .. components are collapsed before the path reaches the filesystem, so the directories outside the destination are never created.(CVE-2026-19672) In CPython 3.13 and earlier, the tarfile module's data and tar extraction filters are vulnerable to crafted archives containing a hard link to a symbolic link. Such archives may cause extraction to modify the permissions or modification time of a file outside the destination directory, or expose the contents of that file within the extracted tree.(CVE-2026-82049) When tarfile extracts a link on a system that doesn't support links, it falls back to extracting a member from the archive. In this case, the filter function is run twice: once for the extracted member, and once with name set to the location of the link. For one of the calls, the return value was ignored. Instead, the member should be skipped if either call returns None.(CVE-2026-87910)
CVSS v4.0
Affected software
pkg:rpm/openEuler/python3&distro=openEuler-24.03-LTS-SP4Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The urllib.request module's HTTPPasswordMgr classes did not consider URL schemes when matching credentials, allowing credentials for HTTPS URLs to be sent over HTTP and vice versa, risking credential exposure via downgrade or redirect attacks (CVE-2026-15806). The stringprep module incorrectly processed certain Unicode characters, causing mismatches in domain name processing with IDNA 2003 (CVE-2026-17084). The csv.Sniffer.sniff() method can be exploited with crafted CSV input to cause super-linear regex processing and high CPU usage (CVE-2026-18503). The tarfile module's extraction filters could create directories outside the intended destination on POSIX systems due to improper path handling (CVE-2026-19672), and crafted archives with hard links to symbolic links could modify files outside the extraction directory or expose their contents (CVE-2026-82049). Additionally, tarfile extraction filters mishandled fallback extraction on systems without link support, potentially skipping necessary checks (CVE-2026-87910).
Potential Impact
These vulnerabilities can lead to credential exposure through improper credential reuse across HTTP and HTTPS schemes, denial of service via CPU exhaustion, incorrect domain name processing affecting applications relying on stringprep, and potential unauthorized file system modifications or information disclosure during archive extraction. The impact ranges from credential compromise to resource exhaustion and file system integrity issues.
Mitigation Recommendations
An official patch is available addressing these vulnerabilities. Users should upgrade to Python versions at or beyond 3.11.6-45.oe2403sp4 or the corresponding patched releases. Applying these updates will mitigate the credential exposure, CPU exhaustion, Unicode processing, and tarfile extraction vulnerabilities. No additional mitigation actions are required beyond applying the official fixes.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- OESA-2026-4011
- Osv Schema Version
- 1.7.2
- Ecosystems
- ["openEuler:24.03-LTS-SP4"]
- Database Specific Severity
- High
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ab5fb9cf7a7c5410655d1e7
Added to database: 09/25/2026, 04:42:04 UTC
Last enriched: 09/25/2026, 04:47:25 UTC
Last updated: 09/26/2026, 03:47:33 UTC
Views: 18
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