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CVE-2023-6549 Citrix CVE debrief

CVE-2023-6549 is a Citrix NetScaler ADC and NetScaler Gateway buffer overflow vulnerability that CISA added to its Known Exploited Vulnerabilities (KEV) catalog on 2024-01-17. For defenders, the key signal is not just the weakness class but the KEV status: CISA set a remediation due date of 2024-02-07 and instructed organizations to apply vendor mitigations or discontinue use if mitigations are unavailable.

Vendor
Citrix
Product
NetScaler ADC and NetScaler Gateway
CVSS
HIGH 8.2
CISA KEV
Listed
Original CVE published
2024-01-17
Original CVE updated
2024-01-17
Advisory published
2024-01-17
Advisory updated
2024-01-17

Who should care

Organizations that operate Citrix NetScaler ADC or NetScaler Gateway appliances, especially internet-facing deployments; security teams responsible for patching, mitigation tracking, and exposure management; and incident response teams monitoring KEV-listed issues.

Technical summary

The public record identifies the issue as a buffer overflow in Citrix NetScaler ADC and NetScaler Gateway. CISA’s KEV entry marks it as a known exploited vulnerability and points defenders to Citrix’s security bulletin for mitigation guidance.

Defensive priority

High. KEV inclusion means CISA considers this vulnerability actively exploited in the wild, so exposed Citrix NetScaler deployments should be prioritized immediately against vendor guidance and remediation timelines.

Recommended defensive actions

  • Review Citrix’s security bulletin referenced by CISA for CVE-2023-6549 and follow the vendor’s mitigation instructions.
  • If mitigations are unavailable or cannot be deployed quickly, discontinue use of the affected product as CISA advises.
  • Inventory all Citrix NetScaler ADC and NetScaler Gateway instances, especially those reachable from the internet.
  • Confirm whether your environment was still running affected versions during the KEV remediation window.
  • Track remediation status against the CISA KEV due date and verify that compensating controls remain in place until full remediation is complete.

Evidence notes

This debrief is based on the supplied CVE record, CISA KEV source item, and official resource links. Supported facts include: the vulnerability name/class (buffer overflow), the affected product family (Citrix NetScaler ADC and NetScaler Gateway), KEV listing date (2024-01-17), and the due date (2024-02-07). The source item notes cite Citrix support article CTX584986 and the NVD record as official references. No CVSS score or exploit detail was supplied in the corpus.

Sources and references

Verified primary and authoritative sources

  • CVE-2023-6549 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2023-6549

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2023-6549 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2023-6549

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.