DNS rebinding bypasses SSRF protection in Apache Fesod
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.
Summary
Apache Fesod (Incubating) fesod-sheet 2.0.2-incubating is affected by a server-side request forgery flaw in the UrlImageConverter component (CWE-918). The converter checks the resolved IP addresses of an image URL hostname, then opens a separate connection that can resolve the hostname again. An unauthenticated remote attacker who controls the DNS responses for that hostname can make the connection reach a restricted address after validation, when an application accepts attacker-controlled image URLs for spreadsheet writing.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
Description from the CNA
Server-Side Request Forgery (SSRF) protection in the UrlImageConverter component of Apache Fesod (Incubating) fesod-sheet 2.0.2-incubating can be bypassed through DNS rebinding. When an application accepts an attacker-controlled image URL for spreadsheet writing, the converter checks the hostname's resolved IP addresses and then opens a separate connection that can resolve the hostname again. An attacker who controls DNS responses for the URL hostname may cause the connection to reach a restricted address after validation. CVE-2026-49328 covers SSRF in releases before 2.0.2-incubating; this issue is a DNS rebinding bypass of the protection in 2.0.2-incubating. Apache Fesod (Incubating) 2.1.0-incubating addresses the reported default-fetch scenario by disabling remote URL image fetching by default and requiring an explicit exact-host allowlist when the feature is enabled. Users should upgrade to 2.1.0-incubating. Applications enabling remote URL image fetching should allowlist only hostnames whose DNS and HTTP services are trusted.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade to Apache Fesod (Incubating) 2.1.0-incubating, which addresses the reported default-fetch scenario by disabling remote URL image fetching by default and requiring an explicit exact-host allowlist when the feature is enabled. Applications that enable remote URL image fetching should allowlist only hostnames whose DNS and HTTP services are trusted.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
Timeline
- 2026-10-13 Threatist record created from CVE-2026-107460
- 2026-10-13 Alias added: GHSA-vf6f-333q-84g4
- 2026-10-20 CVSS score added · CISA ADP
- 2026-10-20 CISA SSVC decision points changed
- 2026-10-20 Priority changed: LOW → MEDIUM
References
More Apache vulnerabilities
- TI-2025-18529 Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUT KEVCVSS 3.1CRITICAL 10.0
- TI-2024-30292 Apache OFBiz: Confused controller-view authorization logic (forced browsing) KEVCVSS 3.1CRITICAL 9.8
- TI-2024-26062 Apache OFBiz: Unauthenticated endpoint could allow execution of screen rendering code KEVCVSS 3.1CRITICAL 9.8
- TI-2024-21190 Apache OFBiz: Path traversal leading to RCE KEVCVSS 3.1CRITICAL 9.8
- TI-2024-18186 Apache HugeGraph-Server: Command execution in gremlin KEVCVSS 3.1CRITICAL 9.8
- TI-2023-25106 Deserialization of untrusted data in Apache ActiveMQ KEVCVSS 3.1CRITICAL 10.0
Sources
- CVE-2026-107460 · CVE Program
- CVE-2026-107460 · NVD
- FIRST EPSS
- GHSA-vf6f-333q-84g4 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences