CVE-2016-5421: canonical ubuntu_linux Use After Free
Vulnerability summary
CVE-2016-5421 is a high (CVSS 8.1) Use After Free vulnerability in canonical ubuntu_linux. EPSS estimates a 8.04% chance of exploitation in the next 30 days, higher than 94.7% of scored vulnerabilities.
Severe, CVSS 8.1 (NVD); no exploitation reported by the 5 checked sources; EPSS 8% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 5 · Related 2Timeline
- 10-08-2016PublishedVulnerability first disclosed.
- 06-08-2024Last modifiedVulnerability information updated.
Description
Use-after-free vulnerability in libcurl before 7.50.1 allows attackers to control which connection is used or possibly have unspecified other impact via unknown vectors.
CVSS metrics
6 scores · 4 sources · 3 versions- OSV · AlpineEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
8.04%
Chance of exploitation in the next 30 days
Percentile
95%
Versus all other CVEs
30-day change
No change 0.00 pp
From 8.04% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian2 products
- curl< 7.50.1-1
- debian_linuxEOL8.0
Alpine1 product
- curl< 7.50.1-r0 | < 7.50.1 | < 7.49.1-r1
Canonical1 product
- ubuntu_linuxEOL12.04 | 14.04 | 16.04
Fedoraproject1 product
- fedoraEOL23 | 24
Haxx1 product
- libcurl≤ 7.50.0
Ubuntu1 product
- curl< 7.35.0-1ubuntu2.8 | < 7.47.0-1ubuntu2.1
7 vendors · 9 products
References
20 links- www.slackware.com/security/viewer.php?l=slackware-security&y=2016&m=slackware-security.563059Vendor AdvisoryX Refsource SLACKWAREThird Party Advisory
- lists.opensuse.org/opensuse-updates/2016-09/msg00011.htmlVendor AdvisoryX Refsource SUSEThird Party Advisory
- lists.opensuse.org/opensuse-updates/2016-09/msg00094.htmlVendor AdvisoryX Refsource SUSEThird Party Advisory
Show all 20 references
- www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.htmlX Refsource CONFIRMPatchThird Party Advisory