CVE-2021-20254
Reported by redhat · Published May 5, 2021
A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.
Fixed versions
Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.
| Package | Ecosystem | Fixed in |
|---|---|---|
| samba-libs | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| libsmbclient | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| samba-test | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| samba-common-libs | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| libwbclient | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| samba-winbind-modules | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| samba-client-libs | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| samba-winbind | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| samba-winbind-krb5-locator | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| samba-common-tools | Amazon Linux | 4.10.16-15.amzn2.0.1 |
| samba | Ubuntu:18.04:LTS | 2:4.7.6+dfsg~ubuntu-0ubuntu2.23 |
| samba | Ubuntu:16.04:LTS | 2:4.3.11+dfsg-0ubuntu0.16.04.34 |
1 more packages have a fixed version. See every fix in Lookup.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| n/a | samba | samba 4.14.1, samba 4.13.6, samba 4.12.13 |
| n/a | samba | samba 4.14.1, samba 4.13.6, samba 4.12.13 |
Timeline
- Apr 28, 2021 CVE Published
- May 6, 2021 EPSS Score (30 in total, the first dated here)
- Aug 3, 2024 CVE Updated
- Mar 7, 2026 Distribution Patch (8 in total, the first dated here)
- Mar 7, 2026 Security Advisory (12 in total, the first dated here)
- Aug 27, 2026 Coalition ESS Score
Query this with the API
The same record, from the CLI:
vulnetix vdb vuln CVE-2021-20254
vulnetix vdb fixes CVE-2021-20254Or with curl, using the org id and key from your account page:
curl -s -H "Authorization: ApiKey ${VULNETIX_ORG_ID}:${VULNETIX_API_KEY}" \
"https://api.vdb.vulnetix.com/v2/vuln/CVE-2021-20254/fixes/registry"The Community plan is free and allows 50 queries a day. Get a free API key · API quickstart
References
- x_refsource_MISC
- x_refsource_MISC
- x_refsource_MISC
- FEDORA-2021-1d0807008b vendor-advisoryx_refsource_FEDORA
- FEDORA-2021-7026246ea9 vendor-advisoryx_refsource_FEDORA
- GLSA-202105-22 vendor-advisoryx_refsource_GENTOO
- [debian-lts-announce] 20210529 [SECURITY] [DLA 2668-1] samba security update mailing-listx_refsource_MLIST