CVE-2021-33636

Host code execution via untrusted NSS library loading

Published Oct 29, 2023 · Updated Sep 9, 2024

Code injection in the image module of openEuler iSulad allows local users to execute arbitrary code by loading a malicious image. The util_archive.c archive path enters the image chroot before glibc initializes Name Service Switch libraries, so the dynamic loader resolves an NSS module from the untrusted image filesystem. Local access to invoke isula load is required, and successful exploitation hijacks the iSulad process context.

CVSS severity8.4
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in the image module of openEuler iSulad allows local users to execute arbitrary code by loading a malicious image. The util_archive.c archive path enters the image chroot before glibc initializes Name Service Switch libraries, so the dynamic loader resolves an NSS module from the untrusted image filesystem. Local access to invoke isula load is required, and successful exploitation hijacks the iSulad process context.

The record

CVE
CVE-2021-33636
Published
Oct 29, 2023
Updated
Sep 9, 2024
Vendor
openEuler
Product
iSulad
Classifications
CWE-665, CWE-94, CAPEC-234, T1574.006
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 29, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.0.8-20210518.144540.git5288ed93,2.0.18-10,2.1.2
  2. Affected versionversion=0 <=2.0.8-20210518.144540.git5288ed93,2.0.18-10,2.1.2 changes=[{"at":"0102-fix-loading-of-nsswitch-based-config-inside-chr.patch","status":"unaffected"},{"at":"0106-fix-loading-of-nsswitch-based-config-inside-chroot-u.patch","status":"unaffected"}]

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

openEuler · iSuladversion=0 <=2.0.8-20210518.144540.git5288ed93,2.0.18-10,2.1.2; version=0 <=2.0.8-20210518.144540.git5288ed93,2.0.18-10,2.1.2 changes=[{"at":"0102-fix-loading-of-nsswitch-based-config-inside-chr.patch","status":"unaffected"},{"at":"0106-fix-loading-of-nsswitch-based-config-inside-chroot-u.patch","status":"unaffected"}]

Published CVSS scores

8.4openEulerCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-665Improper Initialization
CWE-94Improper Control of Generation of Code ('Code Injection')
CAPEC-234Hijacking a Privileged Process
T1574.006Dynamic Linker Hijacking

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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