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Fencer Intel
medium 4.3

CVE-2021-4249 json

xml-conduit DOCTYPE Entity Expansion Parse.hs infinite loop

published 3y ago modified 4mo ago also EUVD-2021-34096 , HSEC-2023-0004

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

A vulnerability was found in xml-conduit. It has been classified as problematic. Affected is an unknown function of the file xml-conduit/src/Text/XML/Stream/Parse.hs of the component DOCTYPE Entity Expansion Handler. The manipulation leads to infinite loop. It is possible to launch the attack remotely. Upgrading to version 1.9.1.0 is able to address this issue. The name of the patch is 4be1021791dcdee8b164d239433a2043dc0939ea. It is recommended to upgrade the affected component. The identifier of this vulnerability is VDB-216204.

Patch / fix

  • hackage xml-conduit 1.9.1.0
  • haskell xml-conduit 1.9.1.0
  • haskell-xml-conduit Debian 14, Debian 13, Debian 12 1.9.1.1-1

debian advisories DEBIAN-CVE-2021-4249

  • ghc-xml-conduit openSUSE Tumbleweed 1.10.1.0-2.1

opensuse advisories openSUSE-SU-2026:11086-1

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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-2021-4249 updated cvss 4.3

ghc-xml-conduit: infinite loop via crafted xml

  • 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
none
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.84% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
hackage xml-conduit
>=0.5.0, <1.9.1.0
1.9.1.0

Affected products

  • unspecified xml-conduit

Classification

Weakness
  • CWE-404 Improper Resource Shutdown or Release

References

Sources

Fencer Intel 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.