How severe is CVE-2026-39843?

CVE-2026-39843 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-39843 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39843?

CVE-2026-39843 affects Plane. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39843?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-39843 have an EU (EUVD) identifier?

Yes. CVE-2026-39843 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20940.

When was CVE-2026-39843 published?

CVE-2026-39843 was published on 2026-04-09 and last updated on 2026-06-17.

CVE-2026-39843

CVE-2026-39843 is a high-severity vulnerability in Plane with a CVSS 3.x base score of 7.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-918.

Key facts

Severity: High (CVSS 3.x base score 7.7)
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20940
Weakness: CWE-918
Affected product: Plane
Published: 2026-04-09
Last modified: 2026-06-17

Description

Plane is an an open-source project management tool. From 0.28.0 to before 1.3.0, the remediation of GHSA-jcc6-f9v6-f7jw is incomplete which could lead to the same full read Server-Side Request Forgery when a normal html page contains a link tag with an href that redirects to a private IP address is supplied to Add link by an authenticated attacker with low privileges. Redirects for the main page URL are validated, but not the favicon fetch path. fetch_and_encode_favicon() still uses requests.get(favicon_url, ...) with the default redirect-following. This vulnerability is fixed in 1.3.0.

Frequently asked questions

What is CVE-2026-39843?: Plane is an an open-source project management tool. From 0.28.0 to before 1.3.0, the remediation of GHSA-jcc6-f9v6-f7jw is incomplete which could lead to the same full read Server-Side Request Forgery when a normal html page contains a link tag with an href that redirects to a private IP address is supplied to Add link by an authenticated attacker with low privileges. Redirects for the main page URL are validated, but not the favicon fetch path. fetch_and_encode_favicon() still uses requests.get(favicon_url, ...) with the default redirect-following. This vulnerability is fixed in 1.3.0.
How severe is CVE-2026-39843?: CVE-2026-39843 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-39843 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39843?: CVE-2026-39843 affects Plane. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39843?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-39843 have an EU (EUVD) identifier?: Yes. CVE-2026-39843 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20940.
When was CVE-2026-39843 published?: CVE-2026-39843 was published on 2026-04-09 and last updated on 2026-06-17.

References

https://github.com/makeplane/plane/security/advisories/GHSA-9fr2-pprw-pp9j

Affected products (1)

cpe:2.3:a:plane:plane:*:*:*:*:*:*:*:*

More vulnerabilities in Plane

CVE-2024-47830 — Critical (CVSS 9.3): Plane is an open-source project management tool. Plane uses the ** wildcard support to retrieve the image from any…
CVE-2026-30242 — High (CVSS 8.5): Plane is an an open-source project management tool. Prior to version 1.2.3, the webhook URL validation in…
CVE-2026-46558 — High (CVSS 8.3): Plane is an open-source project management tool. Prior to version 1.3.1, there is a cross-workspace asset authorization…
CVE-2026-27706 — High (CVSS 7.7): Plane is an an open-source project management tool. Prior to version 1.2.2, a Full Read Server-Side Request Forgery…
CVE-2026-30244 — High (CVSS 7.5): Plane is an an open-source project management tool. Prior to version 1.2.2, unauthenticated attackers can enumerate…
CVE-2023-30791 — High (CVSS 7.1): Plane version 0.7.1-dev allows an attacker to change the avatar of his profile, which allows uploading files with HTML…

All CVEs affecting Plane →

Other CWE-918 (Server-Side Request Forgery (SSRF)) vulnerabilities

CVE-2026-47938 — Critical (CVSS 10.0): Adobe Campaign Classic (ACC) versions 7.4.3 build 9394 and earlier are affected by a Server-Side Request Forgery (SSRF)…
CVE-2026-35431 — Critical (CVSS 10.0): Server-side request forgery (ssrf) in Microsoft Entra ID Entitlement Management allows an unauthorized attacker to…
CVE-2026-32186 — Critical (CVSS 10.0): Server-side request forgery (ssrf) in Microsoft Bing allows an unauthorized attacker to elevate privileges over a…
CVE-2026-33107 — Critical (CVSS 10.0): Server-side request forgery (ssrf) in Azure Databricks allows an unauthorized attacker to elevate privileges over a…
CVE-2026-32871 — Critical (CVSS 10.0): FastMCP is a Pythonic way to build MCP servers and clients. Prior to version 3.2.0, the OpenAPIProvider in FastMCP…
CVE-2026-32169 — Critical (CVSS 10.0): Server-side request forgery (ssrf) in Azure Cloud Shell allows an unauthorized attacker to elevate privileges over a…

Browse all CWE-918 (Server-Side Request Forgery (SSRF)) vulnerabilities →