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sos clean EUVDEUVD-2026-65492

| CVE-2026-79655 HIGH
Improper Link Resolution Before File Access (CWE-59)
2026-08-25 redhat GHSA-jhqm-m4j3-wqq2
7.8
CVSS 3.1 · Vendor: redhat
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Craft malicious tar with symlink escape
  2. Delivery
    Deliver archive to target operator
  3. Exploit
    Operator runs sos clean as root
  4. Execution
    Extraction follows out-of-tree symlink
  5. Persist
    Attacker file written to arbitrary system path
  6. Impact
    Persistence or privilege escalation achieved

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V5 - File Handling Symlink resolution safety
Exploitation Conditions

Exploitation requires that an attacker supply a specially crafted tar archive and that a privileged user (typically root) processes that archive using the sos clean command. The sos clean process must have write access to the target path - since it commonly runs as root, no additional file permission barrier exists. The CVSS UI:R metric confirms that a human operator must actively invoke sos clean on the malicious archive; fully automated exploitation against systems without operator interaction is not possible. Non-default configurations or specific feature flags are not required - this affects the default sos clean extraction path on all RHEL 6-10 systems with the unpatched sos package installed. Exploitation is limited by the requirement that the attacker either have local access to deliver the archive or control an archive-delivery channel trusted by the target operator (e.g., a shared support portal or automated pipeline ingesting external sosreports).

Impact

The CVSS 3.1 base score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) reflects a realistic threat model: the attacker crafts a malicious archive (no privileges required) and must induce a privileged user to process it with sos clean (UI:R). The local attack vector (AV:L) constrains automated scanning at internet scale, but in enterprise environments where sosreport archives are routinely shared with support teams or processed by automated pipelines, the effective barrier is lower than AV:L implies. The AC:L rating is accurate - archive crafting requires no special conditions once the technique is understood. The C:H rating is defensible because a well-crafted archive could overwrite cron jobs, sudoers, or SSH authorized_keys, achieving full system compromise including confidentiality. EPSS data was not provided in the input; without it, probabilistic exploitation frequency cannot be quantified. No KEV listing and no identified public POC reduce immediate urgency, though the GitHub issue (#4460) and PR (#4461) are public and sufficient for a competent attacker to reconstruct the technique. The highest real-world risk is in CI/CD or support workflows that automatically process untrusted sosreport archives as root.

Exploit ScenarioDerived

An attacker with the ability to supply a sosreport tar archive to a system administrator persuades or tricks the administrator into running sos clean on the malicious archive as root. The archive contains a symlink member pointing to /etc and a subsequent file member under the same relative path; during extraction, sos clean follows the symlink and writes the attacker-controlled file content to /etc/cron.d/backdoor or /etc/sudoers.d/pwned, achieving persistent privilege escalation. The GitHub issue and PR are public, providing enough detail to reconstruct this technique without a standalone POC.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 25, 2026

Arbitrary file write via path traversal in the sos clean utility allows a local attacker to overwrite or create files at any location on the system by supplying a crafted tar archive to a privileged operator. The vulnerability exists across all supported Red Hat Enterprise Linux versions (6 through 10) and stems from sos clean's use of Python's fully_trusted_filter (or its legacy equivalent) during tar extraction, which performs no validation of symlink or hardlink targets - permitting escape from the intended extraction directory. Because sos clean commonly runs as root, successful exploitation yields full system compromise. No public exploit code has been identified at time of analysis and the vulnerability is not listed in CISA KEV.

RemediationAI

The upstream fix is available as GitHub PR #4461 (https://github.com/sosreport/sos/pull/4461), which replaces the fully_trusted_filter extraction path with a hardened _make_safer_extract_filter that validates both member paths and symlink/hardlink targets against the destination directory. A released, tagged version containing this fix has not been independently confirmed from the provided data - monitor the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-79655 and the sos upstream releases for a patched package version. As a compensating control where patching is not immediately possible, restrict who can invoke sos clean on archives from untrusted sources - specifically, avoid running sos clean as root against archives received from external parties or shared via untrusted channels. Running sos clean inside a container or with a limited filesystem namespace (e.g., systemd-run with ReadOnlyPaths or a restricted mount namespace) would prevent writes outside the extraction directory and constitutes an effective containment measure with the trade-off of requiring operational changes to the support workflow.

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Technical ContextAI · show details

The sos package is a system diagnostic tool shipped with Red Hat Enterprise Linux; its sos clean subcommand processes sosreport tar archives to scrub sensitive data. Internally, Python's tarfile module is used for extraction. Prior to the fix, sos clean set archive.extraction_filter to tarfile.fully_trusted_filter (or a pass-through lambda on older Pythons), explicitly bypassing the path-traversal protections introduced in PEP-706 and Python 3.12. CWE-59 (Improper Link Resolution Before File Access, 'Link Following') describes the root cause: symlink and hardlink member entries inside the tar archive were extracted without verifying that their targets resolved within the destination directory. An attacker can include a symlink member pointing to an absolute path (e.g., /etc) and follow it with a regular-file member under the same relative path, causing the file to be written to the absolute target. The fix in GitHub PR #4461 introduces _make_safer_extract_filter, which uses os.path.commonpath to confirm both the member path and any link target stay within abs_dest, and falls back to Python 3.12+ tarfile.data_filter when available. Affected CPEs span cpe:2.3:a:red_hat:red_hat_enterprise_linux_6 through 10.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (redhat) PRIMARY 7.8 HIGH
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
vuln.today AI 7.8 HIGH

AV:L because the malicious archive must be present locally; PR:N because archive crafting requires no privileges; UI:R because a privileged operator must invoke sos clean on the archive.

3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Red Hat 7.8 HIGH

Primary rating from Vendor (redhat).

CVSS VectorVendor: redhat

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

A flaw was found in sos clean, a utility within the sos package. This vulnerability allows a local attacker to perform arbitrary file creation or overwrite. By crafting a malicious tar archive, an attacker can exploit a path traversal issue during tar extraction, where symlink and hardlink targets are not properly validated. This enables the attacker to write files to arbitrary locations on the system with the privileges of the sos clean process, which often runs as root.

Executive ViewAI

Why It Matters

CVE-2026-79655 in Red Hat's sos clean utility allows local attackers to write arbitrary files anywhere on systems when a privileged operator processes a malicious tar archive. Since sos clean typically runs as root, exploitation results in complete system compromise across all supported RHEL versions (6-10), exposing organizations to critical infrastructure and data loss.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Implement strict access controls via sudoers configuration limiting sos clean execution to minimal set of authorized administrators; require human inspection and code review of all tar archives before processing; deploy file integrity monitoring to detect unauthorized file creation or modification; monitor and alert on all sos clean command execution; consider running sos diagnostics in isolated containers to contain potential compromise; establish secure handling procedures ensuring tar archives come from verified sources only.

Threat Intelligence Overview

EPSS Score
0.1%
Top 96% exploitable
Prevalence
Medium
standard diagnostic tool in Red Hat Enterprise Linux ecosystems
Data Quality
7 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment MSRC Vendor GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
Poc
System Exposure· derived
Small
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +39
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Path traversal exploits occur when applications use user-controlled input to construct file system paths without proper validation.

Affected Products (CPE)CVE.org

cpe:2.3:a:red_hat:red_hat_enterprise_linux_10:*:*:*:*:*:*:*:*
cpe:2.3:a:red_hat:red_hat_enterprise_linux_6:*:*:*:*:*:*:*:*
cpe:2.3:a:red_hat:red_hat_enterprise_linux_7:*:*:*:*:*:*:*:*
cpe:2.3:a:red_hat:red_hat_enterprise_linux_8:*:*:*:*:*:*:*:*
cpe:2.3:a:red_hat:red_hat_enterprise_linux_9:*:*:*:*:*:*:*:*
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Use-after-free in librsvg during rendering of crafted SVG documents with nested XInclude directives and duplicate entity

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A signed integer overflow vulnerability exists in the libtiff library's putcontig8bitYCbCr44tile function that leads to

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The system CA trust store shipped in Red Hat's ca-certificates RPM packages includes eMudhra root authorities that signe

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Vendor StatusVendor

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