CVE-2021-42056Public exploit

Root privilege escalation via temporary-file symlinks

Published Jun 24, 2022 · Updated Aug 4, 2024

Link-following in Thales SafeNet Authentication Client 10.7.7 and earlier allows local users to overwrite arbitrary files. Root-running SACSrv creates predictable eToken.hid and eToken.lock files with world-writable permissions and follows attacker-placed symbolic links when updating them. Local filesystem access enables root command execution on Linux; the disclosure did not demonstrate an equivalent symlink exploit on Windows.

CVSS severity6.7
Medium
EPSS probability1.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Link-following in Thales SafeNet Authentication Client 10.7.7 and earlier allows local users to overwrite arbitrary files. Root-running SACSrv creates predictable eToken.hid and eToken.lock files with world-writable permissions and follows attacker-placed symbolic links when updating them. Local filesystem access enables root command execution on Linux; the disclosure did not demonstrate an equivalent symlink exploit on Windows.

The record

CVE
CVE-2021-42056
Published
Jun 24, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-59, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 24, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
T1068Exploitation for Privilege Escalation

Public exploit references

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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