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NVD / CVE Program· CNA redhat

CVE-2026-88839: Busybox: busybox: passwd/group parser writes heap pointers out of bounds due to stale tokenize() endpoint

MediumCVSS 6.7 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 26/100)

  • 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. Administrator privileges are required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: azl3 busybox 1.36.1-27 on Azure Linux 3.0 Release Notes; azl3 busybox 1.36.1-28 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to azl3 busybox 1.36.1-27 on Azure Linux 3.0 Release Notes; azl3 busybox 1.36.1-28 on Azure Linux 3.0 Release Notes 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

BusyBox passwd/group tokenize() references a stale endpoint pointer after trimming, causing an out-of-bounds write of heap pointers.

Published
Sep 23, 2026
Updated
Sep 25, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
6.7
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.

Follow CVE-2026-88839

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 Hardened Images

    • 1.37.0-9.1.hum1 and laternot affected · rpm

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12busyboxfrom 0—
openSUSE:Leap 16.0busyboxbefore 1.37.0-160000.8.11.37.0-160000.8.1
openSUSE:Tumbleweedbusyboxbefore 1.38.0-3.11.38.0-3.1
Red Hat:hummingbird:1busyboxbefore 0:1.37.0-9.1.hum10:1.37.0-9.1.hum1
Red Hat:hummingbird:1busybox-petitbootbefore 0:1.37.0-9.1.hum10:1.37.0-9.1.hum1
Red Hat:hummingbird:1busybox-sharedbefore 0:1.37.0-9.1.hum10:1.37.0-9.1.hum1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSbusyboxbefore 1.35.0-150400.3.23.11.35.0-150400.3.23.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7busyboxbefore 1.37.0-150700.18.24.11.37.0-150700.18.24.1
SUSE:Linux Enterprise Server 12 SP5-LTSSbusyboxbefore 1.35.0-10.12.11.35.0-10.12.1
SUSE:Linux Enterprise Server 16.0busyboxbefore 1.37.0-160000.8.11.37.0-160000.8.1
SUSE:Linux Micro 6.0busyboxbefore 1.36.1-159998.1.11.36.1-159998.1.1

Same product

red hat: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-90954Busybox: busybox: dpkg-deb extraction-root escape via per-ar-member deferred symlink flush
    31Monitor
  • CVE-2026-96512Sudo: sudo: tz environment variable allows bypass of notbefore/notafter time-based authorization
    31Monitor
  • CVE-2026-78410Util-linux: util-linux: restricted bind mounts do not pin the source, allowing x-mount.owner/group/mode redirection
    31Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-88835Sep 23, 2026 · Busybox: busybox: dpkg read_package_field() steps past nul terminator, causing out-of-bounds read on malformed .deb packages
    24Monitor
  • ← EarlierCVE-2026-88837Sep 23, 2026 · Busybox: busybox: httpd misidentifies yescrypt password hashes as plaintext, inverting authentication
    26Monitor
  • Later →CVE-2026-88840Sep 23, 2026 · Busybox: busybox: tls ssl_server reads one byte out of bounds when parsing truncated clienthello
    21Monitor

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
azl3 busybox 1.36.1-27 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 busybox 1.36.1-28 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
opensuse:busybox1.38.0-3.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:busybox0:1.37.0-9.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:busybox-petitboot0:1.37.0-9.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:busybox-shared0:1.37.0-9.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
suse:busybox1.36.1-159998.1.1 · SUSE:Linux Micro 6.0Package 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).

Credits

All researchers

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

Variant candidates

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

  • CVE-2026-888320 days apartBusybox: busybox: romfs volume id parsing performs unbounded memcpy into fixed-size label buffer, causing heap overflow
    29Monitor

Not on record for this CVE: patch commit or PR link · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • Administrator privileges are required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

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

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.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (2 more)

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

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