CVE-2026-87910— tarfile hardlink fallback ignores custom extraction filter rejection via None
Quick assessment
Affected
Python Software Foundation CPython
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
当 在不支持硬链接或符号链接的系统上解包链接时，它会回退为直接解包归档中的对应成员。在这种情况下，过滤函数会被执行两次：一次用于被解包的成员，另一次则是将 参数设置为该链接的目标路径。而在其中一次调用中，过滤函数的返回值被忽略了。正确的行为应该是：只要任意一次调用返回 ，该成员就应当被跳过。
Possible ATT&CK Techniques 3 AI
T1210 · Exploitation of Remote Services T1559 · Inter-Process Communication T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-87910
Vulnerability Information
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Vulnerability Title
tarfile hardlink fallback ignores custom extraction filter rejection via None
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Python Software Foundation | CPython | 0 ~ 3.16.0 | - |
|
II. Public POCs for CVE-2026-87910
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-87910 (1)
Mailing List Discussions for CVE-2026-87910 (1)
Other References for CVE-2026-87910 (1)
IV. Related Vulnerabilities
Same product: CPython
-
CVE-2026-15310
zipfile: bzip2/LZMA/Zstandard members decompress without a m -
CVE-2026-19672
tarfile extraction filter bypass allows creation of director -
CVE-2026-15806
`HTTPPasswordMgr` can send saved HTTPS credentials via HTTP -
CVE-2026-17084
stringprep.map_table_b2() deviates from RFC 3454 Table B.2 -
CVE-2026-18503
Super-linear CPU usage for unbounded input to csv.Sniffer.sn
Same vendor: Python Software Foundation
-
CVE-2026-15310
zipfile: bzip2/LZMA/Zstandard members decompress without a m -
CVE-2026-19672
tarfile extraction filter bypass allows creation of director -
CVE-2026-15806
`HTTPPasswordMgr` can send saved HTTPS credentials via HTTP -
CVE-2026-17084
stringprep.map_table_b2() deviates from RFC 3454 Table B.2 -
CVE-2026-18503
Super-linear CPU usage for unbounded input to csv.Sniffer.sn
Same weakness: CWE-22
V. Comments for CVE-2026-87910
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