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Fencer Vulns
medium 6.5

CVE-2018-20349 json

NULL pointer dereference vulnerability

published 2018-12-22 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-12907 , RSEC-2023-4

cvss
6.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

The igraph_i_strdiff function in igraph_trie.c in igraph through 0.7.1 has an NULL pointer dereference that allows attackers to cause a denial of service (application crash) via a crafted object.

Patch / fix

  • cran igraph 1.2.2-2
  • igraph Debian 14, Debian 13, Debian 12 0.7.1-3
  • r-cran-igraph Debian 14, Debian 13, Debian 12 1.2.2-2

debian advisories DEBIAN-CVE-2018-20349

  • igraph Ubuntu 16.04 LTS 0.7.1-2.1+deb9u1build0.16.04.1
  • igraph Ubuntu 18.04 LTS 0.7.1-2.1+deb9u1build0.18.04.1

ubuntu advisories UBUNTU-CVE-2018-20349

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2018-20349 updated cvss 3.3

igraph: NULL pointer dereference in igraph_i_strdiff function resulting in a denial of service

  • 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

Exploit prediction

1.60% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/igraph/igraph/issues/1141 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 6.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Affected packages

ecosystem package affected fixed in
cran igraph
>=0.7.1, <1.2.2-2
1.2.2-2

Classification

Weakness

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.