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Fencer Intel
high 7.5

CVE-2020-27638 json

receive.c in fastd before v21 allows denial of service (assertion failure) when receiving packets with an invalid type code.

published 6y ago modified 4mo ago also EUVD-2020-20145

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

receive.c in fastd before v21 allows denial of service (assertion failure) when receiving packets with an invalid type code.

Patch / fix

  • fastd_project fastd 21.0
  • fastd Debian 14, Debian 13, Debian 12 21-1

debian advisories DEBIAN-CVE-2020-27638

  • fastd Ubuntu 16.04 LTS 17-4ubuntu0.1
  • fastd Ubuntu 18.04 LTS 18-3ubuntu0.18.04.1
  • fastd Ubuntu 20.04 LTS 18-3ubuntu0.1

ubuntu advisories UBUNTU-CVE-2020-27638

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

Is CVE-2020-27638 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2020-27638 updated cvss 7.5

fastd: DoS'able memory leak on invalid packets

  • 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

2.36% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

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.