Unpatched extfs vulnerabilities are exploitable through suid-mode Apptainer

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Summary

CVECVE-2023-30549
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2023-04-25 21:15:10 UTC
Updated2026-10-23 23:10:00 UTC
DescriptionApptainer is an open source container platform for Linux. There is an ext4 use-after-free flaw that is exploitable through versions of Apptainer < 1.1.0 and installations that include apptainer-suid < 1.1.8 on older operating systems where that CVE has not been patched. That includes Red Hat Enterprise Linux 7, Debian 10 buster (unless the linux-5.10 package is installed), Ubuntu 18.04 bionic and Ubuntu 20.04 focal. Use-after-free flaws in the kernel can be used to attack the kernel for denial of service and potentially for privilege escalation. Apptainer 1.1.8 includes a patch that by default disables mounting of extfs filesystem types in setuid-root mode, while continuing to allow mounting of extfs filesystems in non-setuid "rootless" mode using fuse2fs. Some workarounds are possible. Either do not install apptainer-suid (for versions 1.1.0 through 1.1.7) or set `allow setuid = no` in apptainer.conf. This requires having unprivileged user namespaces enabled and except for apptainer 1.1.x versions will disallow mounting of sif files, extfs files, and squashfs files in addition to other, less significant impacts. (Encrypted sif files are also not supported unprivileged in apptainer 1.1.x.). Alternatively, use the `limit containers` options in apptainer.conf/singularity.conf to limit sif files to trusted users, groups, and/or paths, and set `allow container extfs = no` to disallow mounting of extfs overlay files. The latter option by itself does not disallow mounting of extfs overlay partitions inside SIF files, so that's why the former options are also needed.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.003690000 probability, percentile 0.295630000 (date 2026-10-23)

Problem Types: CWE-416 | CWE-416 CWE-416: Use After Free

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1[email protected]Secondary7.1HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
3.1CNADECLARED7.1HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Lfprojects Apptainer All All All All
Operating System Redhat Enterprise Linux 7.0 All All All
Application Sylabs Singularity All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apptainer Apptainer affected < 1.1.8 Not specified

References

ReferenceSourceLinkTags
Apptainer: Privilege Escalation (GLSA 202311-13) — Gentoo security af854a3a-2127-422b-91ae-364da2661108 security.gentoo.org
Red Hat Customer Portal - Access to 24x7 support and knowledge af854a3a-2127-422b-91ae-364da2661108 access.redhat.com Not Applicable
Linux 5.4.243 [LWN.net] af854a3a-2127-422b-91ae-364da2661108 lwn.net
Release Apptainer 1.1.8 · apptainer/apptainer · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Release Notes
An unpatched ext4 vulnerability is exploitable through setuid-mode Apptainer and Singularity · Advisory · apptainer/apptainer · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Mitigation, Vendor Advisory
Response to CVE-2023-30549 | Sylabs af854a3a-2127-422b-91ae-364da2661108 sylabs.io
CVE-2022-1184 | SUSE af854a3a-2127-422b-91ae-364da2661108 www.suse.com Not Applicable
ext4: avoid a potential slab-out-of-bounds in ext4_group_desc_csum · torvalds/linux@4f04351 · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com
Linux 4.19.283 [LWN.net] af854a3a-2127-422b-91ae-364da2661108 lwn.net
CVE-2022-1184 | Ubuntu af854a3a-2127-422b-91ae-364da2661108 ubuntu.com Not Applicable
ext4: add bounds checking in get_max_inline_xattr_value_size() · torvalds/linux@2220eaf · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com
Merge pull request from GHSA-j4rf-7357-f4cg · apptainer/apptainer@5a4964f · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Patch
CVE-2022-1184 af854a3a-2127-422b-91ae-364da2661108 security-tracker.debian.org Not Applicable
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 505984 Alpine Linux Security Update for apptainer
  • 710792 Gentoo Linux Apptainer Privilege Escalation Vulnerability (GLSA 202311-13)

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