CVE Intelligence
High Memory corruption

CVE-2023-30549 — Unpatched extfs vulnerabilities are exploitable through suid-mode Apptainer

Apptainer 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.

Published Apr 25, 2023 · Updated Oct 23, 2026 · Sources: CVE Program (cve.org) e CISA ADP, NIST National Vulnerability Database, GitHub Security Advisories · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.4% (30-day exploitation probability)+5
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.37%
ahead of 31% of scored CVEs · Oct 27, 2026
Affects
Apptainer
Apptainer and 3 more
CVSS base
7.8
High · 4 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — github.com (NIST National Vulnerability Database)
  • Documented mitigation — github.com (NIST National Vulnerability Database)
  • Go Github.com/apptainer/apptainer: fixed in version 1.1.8 — github.com (GitHub Security Advisories)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Apptainer Apptainer, Lfprojects Apptainer, Red Hat Enterprise Linux…).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Apptainer Apptainer version < 1.1.8 Vulnerable CVE Program (cve.org) e CISA ADP
Lfprojects Apptainer < 1.1.8 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux version 7.0 Vulnerable NIST National Vulnerability Database
Sylabs Singularity versions not specified by the source Vulnerable NIST National Vulnerability Database
Go Github.com/apptainer/apptainer < 1.1.8 Vulnerable GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.8 CVSS 3.1 High 1.8 5.9 nvd@nist.gov via NIST National Vulnerability Database
7.1 CVSS 3.1 High 2.5 4.0 security-advisories@github.com via NIST National Vulnerability Database
7.1 CVSS 3.1 High — — GitHub_M via CVE Program (cve.org) e CISA ADP
7.0 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)
Sources assign different scores within the same severity band. For prioritization we use 7.8 (NVD (NIST)) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-416 · Use After Free

Other CVEs with this weakness →

EPSS over time FIRST

Oct 23, 2026 → Oct 27, 2026 · 5 reading(s) · max 0.37%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
endpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 23, 2026 · GitHub Security Advisories
  • Affected products added · go/github.com/apptainer/apptainer
    Oct 23, 2026 · GitHub Security Advisories
  • Fix documented
    Oct 23, 2026 · NIST National Vulnerability Database
  • Affected products added · lfprojects/apptainer, sylabs/singularity, redhat/enterprise linux
    Oct 23, 2026 · NIST National Vulnerability Database
  • CVSS changed · 7.1 → 7.8
    Oct 23, 2026 · NIST National Vulnerability Database
  • Source status changed · Published → Modified
    Oct 23, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 23, 2026
  • Affected products added · apptainer/apptainer
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • CVSS changed · 7.1
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • Record created in this database
    Oct 23, 2026 · Alertas do Telegram
  • 2023
  • CVE published
    Apr 25, 2023 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 23, 2026 – Oct 23, 2026
  • 1× Official description updated · Oct 23, 2026 – Oct 23, 2026

References

18 on the record

Elsewhere on this site

Apptainer
every CVE for this vendor
Memory corruption
same class
CWE-416
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-104045 Sssd: sssd: denial of service via race condition in autofs responder 21d
  • CVE-2026-104046 Sssd: sssd: denial of service via incomplete identity provider authentication requests 21d
  • CVE-2026-104047 Sssd: sssd: information disclosure via query injection in entra id lookups 21d
  • CVE-2026-104048 Sssd: sssd: authorization bypass via cross-domain username collision in hbac evaluation 21d
  • CVE-2026-88252 Sssd: sssd: denial of service via responder connection retry loop during file descriptor exhaustion 22d
  • CVE-2026-104040 Sssd: sssd: information disclosure via odata injection in entra id lookups 22d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2023-30549 is "Unpatched extfs vulnerabilities are exploitable through suid-mode Apptainer", rated High. It affects Apptainer (Apptainer); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.37% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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