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PatchSiren cyber security CVE debrief

CVE-2019-9621 Synacor CVE debrief

CVE-2019-9621 is identified in the supplied corpus as a server-side request forgery (SSRF) vulnerability in Synacor Zimbra Collaboration Suite (ZCS). CISA lists it in the Known Exploited Vulnerabilities (KEV) catalog, which makes it a higher-priority defensive item even though no CVSS score was supplied here. The supplied timeline shows CISA adding the entry on 2025-07-07 with a remediation due date of 2025-07-28.

Vendor
Synacor
Product
Zimbra Collaboration Suite (ZCS)
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2025-07-07
Original CVE updated
2025-07-07
Advisory published
2025-07-07
Advisory updated
2025-07-07

Who should care

Zimbra Collaboration Suite (ZCS) administrators, email and collaboration platform owners, cloud service operators using Zimbra, incident responders, and vulnerability management teams should treat this as a priority remediation item because it appears in CISA’s KEV catalog.

Technical summary

The available source data only identifies the weakness at a high level: a server-side request forgery (SSRF) issue affecting Synacor Zimbra Collaboration Suite (ZCS). The corpus does not provide affected version ranges, attack preconditions, or exploit mechanics, so the safest interpretation is limited to the product-vulnerability pairing and its KEV status. Because CISA classifies it as known exploited, organizations should assume real-world abuse is plausible and validate whether any ZCS deployment is exposed.

Defensive priority

High. KEV inclusion indicates known exploitation and CISA has assigned a remediation due date. Even without a CVSS score in the supplied data, this should be handled as an urgent patch/mitigation item.

Recommended defensive actions

  • Review Synacor Zimbra Security Advisories and the Zimbra Security Center for vendor mitigation or patch guidance.
  • Apply the vendor-recommended mitigations as soon as possible to any ZCS deployment that is reachable or operationally important.
  • If the product is hosted in a cloud or service context, follow the applicable CISA BOD 22-01 guidance referenced by CISA.
  • If mitigations are unavailable or cannot be applied in time, plan to discontinue use or isolate the affected service until a secure remediation path exists.
  • Inventory all ZCS instances, confirm whether they are externally exposed, and prioritize those with internet-facing access.
  • Monitor logs and outbound/internal request patterns for unexpected SSRF-like activity while remediation is underway.

Evidence notes

Source evidence is limited to the supplied CVE metadata, CISA KEV entry, and official reference links. The corpus confirms: product = Synacor Zimbra Collaboration Suite (ZCS); vulnerability type = SSRF; KEV status = true; dateAdded = 2025-07-07; dueDate = 2025-07-28; knownRansomwareCampaignUse = Unknown. No CVSS score, affected versions, exploit details, or vendor advisory text were provided in the corpus, so none are asserted here beyond the product/vulnerability identification and KEV classification.

Official resources

CISA’s KEV feed lists CVE-2019-9621 on 2025-07-07 with a remediation due date of 2025-07-28. The supplied corpus classifies it as an SSRF issue in Synacor Zimbra Collaboration Suite (ZCS) and does not include additional technical detail.