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CVE-2026-77506 Znuny CVE debrief

CVE-2026-77506 is a medium-severity vulnerability in Znuny before LTS 6.5.22, allowing for AgentTicketEmailResend template XSS. The CVE record was published on 2026-08-20T21:17:10.673Z and was last modified on 2026-09-09T16:04:24.933Z. The NVD entry is currently Deferred. Defenders responsible for Znuny deployments should assess exposure and verify versions, as the vulnerability allows for cross-site scripting (XSS) attacks via the AgentTicketEmailResend template. This vulnerability has a CVSS score of 4.8 and a vector of CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N. To address this vulnerability, defenders should prioritize verifying Znuny versions and assessing exposure to cross-

Vendor
Znuny
Product
Unknown
CVSS
MEDIUM 4.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-20
Original CVE updated
2026-09-09
Advisory published
2026-08-20
Advisory updated
2026-09-09

Who should care

Defenders responsible for Znuny deployments should assess exposure and verify versions, as the vulnerability allows for cross-site scripting (XSS) attacks via the AgentTicketEmailResend template.

Why it matters

CVE-2026-77506 is a medium-severity vulnerability in Znuny before LTS 6.5.22, allowing for AgentTicketEmailResend template XSS. Defenders should prioritize verifying Znuny versions and assessing exposure to prevent potential XSS attacks.

  • Defenders should verify Znuny versions to determine exposure
  • Assess AgentTicketEmailResend template configurations for potential XSS vulnerabilities
  • Implement input validation and sanitization for user-supplied data to prevent XSS attacks

Technical summary

CVE-2026-77506 is a medium-severity vulnerability in Znuny before LTS 6.5.22, allowing for AgentTicketEmailResend template XSS. The vulnerability has a CVSS score of 4.8 and a vector of CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N. This vulnerability allows for cross-site scripting (XSS) attacks via the AgentTicketEmailResend template. To address this vulnerability, defenders should prioritize verifying Znuny versions and assessing exposure to prevent potential XSS attacks. The CVE record and NVD detail page provide information on the vulnerability, including its

Defensive priority

Defenders should prioritize verifying Znuny versions and assessing exposure, as the vulnerability allows for cross-site scripting (XSS) attacks via the AgentTicketEmailResend template.

Recommended defensive actions

  • Verify Znuny version and assess exposure
  • Review AgentTicketEmailResend template configurations
  • Implement input validation and sanitization for user-supplied data

Evidence notes

The CVE record and NVD detail page provide information on the vulnerability, including its CVSS score and vector. However, the exact scope of affected versions and potential impact require further verification.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-77506 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-77506

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

  • CVE-2026-77506 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-77506

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

Supplemental references

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.