CVE-2018-16841: canonical ubuntu_linux Use After Free
Vulnerability summary
CVE-2018-16841 is a medium (CVSS 6.5) Use After Free vulnerability in canonical ubuntu_linux. EPSS estimates a 4.59% chance of exploitation in the next 30 days, higher than 91.5% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 5 · Related 3Timeline
- 28-11-2018PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
Description
Samba from version 4.3.0 and before versions 4.7.12, 4.8.7 and 4.9.3 are vulnerable to a denial of service. When configured to accept smart-card authentication, Samba's KDC will call talloc_free() twice on the same memory if the principal in a validly signed certificate does not match the principal in the AS-REQ. This is only possible after authentication with a trusted certificate. talloc is robust against further corruption from a double-free with talloc_free() and directly calls abort(), terminating the KDC process.
CVSS metrics
8 scores · 5 sources · 3 versions- OSV · AlpineEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- NVDNIST5.7MediumCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HDiffers
EPSS trend
Probability
4.59%
Chance of exploitation in the next 30 days
Percentile
92%
Versus all other CVEs
30-day change
0.00 pp
From 4.59% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
- CWE-415Double FreeThe product calls free() twice on the same memory address.
Affected systems
Debian2 products
- samba< 2:4.9.2+dfsg-2
- debian_linuxEOL9.0
[unknown]1 product
- sambaEOL4.7.12 | 4.8.7 | 4.9.3
Alpine1 product
- samba≥ 4.3.0, < 4.8.7-r0 | ≥ 4.3.0, < 4.6.16-r2 | ≥ 4.3.0, < 4.7.6-r2 | ≥ 4.3.0, < 4.8.8-r0
Canonical1 product
- ubuntu_linuxEOL12.04 | 14.04 | 16.04 | 18.04 | 18.10
Samba1 product
- samba≥ 4.3.0, < 4.7.12 | ≥ 4.8.0, < 4.8.7 | ≥ 4.9.0, < 4.9.3
Ubuntu1 product
- samba< 2:4.3.11+dfsg-0ubuntu0.14.04.19 | < 2:4.3.11+dfsg-0ubuntu0.16.04.18 | < 2:4.7.6+dfsg~ubuntu-0ubuntu2.5
6 vendors · 7 products
References
14 links- bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16841X Refsource CONFIRMIssue TrackingThird Party Advisory
