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CVE Record

CVE-2024-21626: runc container breakout through process.cwd trickery and leaked fds

runc is a CLI tool for spawning and running containers on Linux according to the OCI specification. In runc 1.1.11 and earlier, due to an internal file descriptor leak, an attacker could cause a newly-spawned container process (from runc exec) to have a working directory in the host filesystem namespace, allowing for a container escape by giving access to the host filesystem ("attack 2"). The same attack could be used by a malicious image to allow a container process to gain access to the host filesystem through runc run ("attack 1"). Variants of attacks 1 and 2 could be also be used to overwrite semi-arbitrary host binaries, allowing for complete container escapes ("attack 3a" and "attack 3b"). runc 1.1.12 includes patches for this issue.

HighCVSS 8.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2024-21626 lets certain container starts or exec operations expose the host filesystem to a container process. In business terms, a vulnerable container host could lose the isolation boundary that protects the host and other workloads. The published fix is runc 1.1.12 or vendor backported packages.

Executive priority

Treat as urgent for container-host fleets, especially multi-tenant or untrusted-image environments. It is not KEV-listed in the bundle, but the impact is container escape with host compromise potential. Patch through upstream runc or vendor channels and verify actual deployed runtime versions.

Technical view

runc versions from v1.0.0-rc93 through 1.1.11 leak an internal file descriptor. That can allow a new container process to have its working directory in the host filesystem namespace, enabling host filesystem access and, in variants, overwriting host binaries for full escape. Scope is changed in CVSS, with high confidentiality, integrity, and availability impact.

Likely exposure

Linux container environments using vulnerable runc directly or through a platform package are potentially exposed. The affected range in the bundle is opencontainers runc >=v1.0.0-rc93 and <1.1.12. Exposure depends on the runtime version actually installed, including any vendor backports.

Exploitation context

The bundle marks KEV as false, and the provided sources do not establish active exploitation. The advisory describes realistic abuse through malicious images or runc exec workflows, so environments allowing untrusted images, build inputs, or container exec access deserve priority review.

Researcher notes

Focus validation on runtime provenance, not just application containers. Vendor packages may carry backported fixes without reporting upstream version 1.1.12. The core issue is leaked file descriptors influencing process working directory and host namespace access; avoid reproducing escape behavior in production.

Mitigation direction

  • Upgrade runc to 1.1.12 or later where directly managed.
  • Apply distribution or platform security updates that backport the runc fix.
  • Prioritize hosts running untrusted images or exposing container exec workflows.
  • Check vendor guidance before relying on compensating controls.
  • Refresh base host images after package updates where applicable.

Validation and detection

  • Inventory runc versions across Linux container hosts.
  • Confirm installed versions are 1.1.12 or vendor-fixed builds.
  • Map platforms that package runc indirectly.
  • Review whether untrusted images can be run on affected hosts.
  • Track Debian, Fedora, Red Hat, and upstream advisories to closure.
Prepared
Confidence
high
Sources
11

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-200: Information exposure and cloud metadata lookup

Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-403: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-668: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Container behavior lookup

The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2024-21626 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.6 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
3ADP providers
38Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.6CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H1.86GitHub_M
8.6CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H1.86redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

8.6High
CVSS 3.1 vector shape for CVE-2024-21626Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Reported to Red Hat.

  3. ADP timelineredhat-SADP

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPrunc: file descriptor leak
other:Red Hat severity ratingcvssV3_1
  • 2024-01-17T00:00:00.000Z: Reported to Red Hat.
  • 2024-01-31T20:01:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
opencontainersrunc>=v1.0.0-rc93, < 1.1.12Listed
Weakness

CWE details

CWE-200CWE-403CWE-668

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-200 · source CWE mapping

Exposure of Sensitive Information to an Unauthorized Actor

Exposure of Sensitive Information to an Unauthorized Actor represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-403 · source CWE mapping

Exposure of File Descriptor to Unintended Control Sphere ('File Descriptor Leak')

Exposure of File Descriptor to Unintended Control Sphere ('File Descriptor Leak') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-668 · source CWE mapping

Exposure of Resource to Wrong Sphere

Exposure of Resource to Wrong Sphere represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs