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CVE Record

CVE-2017-17536: Phabricator before 2017-11-10 does not block the --config and --debugger flags to the Mercurial hg program,...

Phabricator before 2017-11-10 does not block the --config and --debugger flags to the Mercurial hg program, which allows remote attackers to execute arbitrary code by using the web UI to browse a branch whose name begins with a --config= or --debugger= substring.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This issue can let a remote user turn a crafted Mercurial branch name into code execution through Phabricator’s web UI. The sources identify vulnerable Phabricator versions as before 2017-11-10. That makes exposure serious for organizations still running old Phabricator with Mercurial repositories visible through the UI.

Executive priority

Treat as high priority for any legacy Phabricator environment using Mercurial. Arbitrary code execution can affect source code integrity, credentials, and build pipelines. If Phabricator is absent or fully updated, priority drops substantially.

Technical view

Phabricator failed to block Mercurial hg flags named in the CVE: --config and --debugger. When browsing a branch whose name begins with those substrings, hg could interpret the branch name as options, leading to arbitrary code execution. The provided sources do not include CVSS, CWE, or detailed affected CPE data.

Likely exposure

Likely limited to Phabricator deployments before 2017-11-10 that use Mercurial repositories and allow web UI branch browsing. The source bundle does not identify specific downstream packages, hosting providers, or maintained forks as affected.

Exploitation context

The CVE describes remote exploitation through the web UI by browsing a specially named branch. The source bundle does not show CISA KEV listing or other evidence of active exploitation in the wild.

Researcher notes

The strongest source fact is the vulnerable condition: Phabricator before 2017-11-10 plus Mercurial branch browsing with branch names starting with --config= or --debugger=. Severity metadata is missing, and the affected block in the bundle is generic, so scope should be validated against deployed Phabricator revisions.

Mitigation direction

  • Upgrade Phabricator to a release or revision dated 2017-11-10 or later.
  • Review the Phabricator task and HackerOne report for vendor-specific remediation details.
  • Restrict repository browsing to trusted users until affected systems are fixed.
  • Review Mercurial repositories for suspicious branch names using the documented prefixes.

Validation and detection

  • Inventory Phabricator instances and confirm their deployed version date or revision.
  • Identify whether Mercurial repositories are enabled and browsable through the web UI.
  • Check repositories for branch names beginning with the risky flag prefixes.
  • Review application and repository access logs for browsing of suspicious branches.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Execution behavior lookup

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CVE-2017-17536 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.