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Fencer Vulns
medium 5.9

CVE-2023-34457 json

MechanicalSoup vulnerable to malicious web server reading arbitrary files on client using file input inside HTML form

published 2023-07-05 3 y ago modified 2026-09-10 1 mo ago also GHSA-x456-3ccm-m6j4 , PYSEC-2023-108 , EUVD-2023-0143

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits
0
none known

Summary

MechanicalSoup is a Python library for automating interaction with websites. Starting in version 0.2.0 and prior to version 1.3.0, a malicious web server can read arbitrary files on the client using a `<input type="file" ...>` inside HTML form. All users of MechanicalSoup's form submission are affected, unless they took very specific (and manual) steps to reset HTML form field values. Version 1.3.0 contains a patch for this issue.

Patch / fix

  • pypi mechanicalsoup 1.3.0
  • mechanicalsoup_project mechanicalsoup 1.3.0
  • python-mechanicalsoup Debian 14, Debian 13 1.3.0-1

debian advisories DEBIAN-CVE-2023-34457

  • python-MechanicalSoup openSUSE Tumbleweed 1.4.0-2.4

opensuse advisories openSUSE-SU-2026:11993-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-34457 updated cvss 5.9

MechanicalSoup: Malicious web server can read arbitrary files on client using file input inside HTML form

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.08% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/MechanicalSoup/MechanicalSoup/security/advisories/GHSA-x456-3ccm-m6j4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
pypi mechanicalsoup
>=0.2.0, <1.3.0
<1.3.0
1.3.0

Affected products

  • MechanicalSoup MechanicalSoup
  • mechanicalsoup_project mechanicalsoup

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.