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NVD / CVE Program· CNA redhat

CVE-2026-88265: Crun: crun: /dev/null symlink follow during stdio reopen allows host bind-mount write and chown

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.12% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: crun (openSUSE:Tumbleweed) 1.30.1-1.1; crun (Red Hat:hummingbird:1) 0:1.30-1.hum1; crun-krun (Red Hat:hummingbird:1) 0:1.30-1.hum1.

Low priority for now. Upgrade to crun (openSUSE:Tumbleweed) 1.30.1-1.1; crun (Red Hat:hummingbird:1) 0:1.30-1.hum1; crun-krun (Red Hat:hummingbird:1) 0:1.30-1.hum1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A flaw was found in crun. After pivot_root, reopening /dev/null for stdio can follow a symlink and attach a host file to container stdio, then change that file's ownership. Affected versions are crun 1.29.1 and earlier. Default configurations that mount a fresh /dev are not exposed. No fixed release is available yet.

MediumCVSS 5.6 · v3.1—No exploit Fix available
Published
Sep 10, 2026
Updated
Oct 2, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
5.6
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Red Hat Red Hat Enterprise Linux 10

    • all versionsaffected

  • Red Hat Red Hat Enterprise Linux 8

    • all versionsaffected

  • Red Hat Red Hat Enterprise Linux 9

    • all versionsaffected

  • Red Hat Red Hat Hardened Images

    • 1.30-1.hum1 and laternot affected · rpm

  • Red Hat Red Hat OpenShift Container Platform 4

    • all versionsaffected
    • all versionsaffected
    • all versionsaffected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12crunfrom 0—
openSUSE:Tumbleweedcrunbefore 1.30.1-1.11.30.1-1.1
Red Hat:hummingbird:1crunbefore 0:1.30-1.hum10:1.30-1.hum1
Red Hat:hummingbird:1crun-krunbefore 0:1.30-1.hum10:1.30-1.hum1
Red Hat:hummingbird:1crun-wasmbefore 0:1.30-1.hum10:1.30-1.hum1

Same product

red hat: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-10230Samba: command injection in wins server hook script
    52Plan
  • CVE-2026-4631Cockpit: cockpit: unauthenticated remote code execution due to ssh command-line argument injection
    44Plan
  • CVE-2026-76578Ipa: freeipa: freeipa: unauthenticated ldap client can obtain administrator credentials via the self-managed-token aci
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-84042Sep 10, 2026 · Crun: crun: rootful krun with passt executes container payload as host root
    31Monitor
  • ← EarlierCVE-2026-84828Sep 10, 2026 · Pcs: pcs: non-root haclient users can read arbitrary files via pcs host auth --token
    26Monitor
  • Later →CVE-2026-88914Sep 10, 2026 · Gstreamer1-plugins-good: gstreamer: integer overflow and out-of-bounds read in qtdemux cea-608 closed-caption parser
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
opensuse:crun1.30.1-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:crun0:1.30-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:crun-krun0:1.30-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:crun-wasm0:1.30-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-877661 days apartBubblewrap: bubblewrap: symlink traversal via /oldroot allows writing files outside sandbox during setup
    35Monitor
  • CVE-2026-7965516 days apartSos: sos: path traversal in sos clean tar extraction via unvalidated symlink/hardlink targets leads to arbitrary file write
    31Monitor
  • CVE-2026-1183792 days apartAnsible-collection-ansible-posix: ansible.posix authorized_key: local privilege escalation via symlink-following chown
    29Monitor
  • CVE-2026-7269430 days apartMrtg: mrtg daemon symlink-following chown allows local privilege escalation via pid file path manipulation
    28Monitor
  • CVE-2026-9627917 days apartFlatpak: flatpak: path traversal issue in oci archive extraction via hardlinks
    26Monitor
  • CVE-2026-11180236 days apartNautilus: nautilus: arbitrary file deletion via trash symlink
    26Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

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

Weakness class (CWE)

CWE-59 · Improper Link Resolution Before File Access ('Link Following')

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records