How severe is CVE-2026-29199?

CVE-2026-29199 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-29199 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-2026-29199?

CVE-2026-29199 affects Phpbb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-29199?

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-2026-29199 have an EU (EUVD) identifier?

Yes. CVE-2026-29199 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26892.

When was CVE-2026-29199 published?

CVE-2026-29199 was published on 2026-05-04 and last updated on 2026-06-17.

CVE-2026-29199

CVE-2026-29199 is a high-severity vulnerability in Phpbb with a CVSS 3.x base score of 8.1. 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-640.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-26892
Weakness: CWE-640
Affected product: Phpbb
Published: 2026-05-04
Last modified: 2026-06-17

Description

phpBB before 3.3.16 is vulnerable to Host Header Injection that can lead to password rest link poisoning. When force_server_vars is disabled, the servers hostname may be extracted from the HTTP Host header which is used to generate the password reset link URL. An attacker who can manipulate the Host header (e.g. through misconfigured host setup or missing header validation by the webserver) can cause password reset emails to contain a link pointing to an attacker-controlled domain, potentially leading to account takeover.

Frequently asked questions

What is CVE-2026-29199?: phpBB before 3.3.16 is vulnerable to Host Header Injection that can lead to password rest link poisoning. When force_server_vars is disabled, the servers hostname may be extracted from the HTTP Host header which is used to generate the password reset link URL. An attacker who can manipulate the Host header (e.g. through misconfigured host setup or missing header validation by the webserver) can cause password reset emails to contain a link pointing to an attacker-controlled domain, potentially leading to account takeover.
How severe is CVE-2026-29199?: CVE-2026-29199 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-29199 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-2026-29199?: CVE-2026-29199 affects Phpbb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-29199?: 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-2026-29199 have an EU (EUVD) identifier?: Yes. CVE-2026-29199 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26892.
When was CVE-2026-29199 published?: CVE-2026-29199 was published on 2026-05-04 and last updated on 2026-06-17.

References

https://hackerone.com/reports/3543246

Affected products (1)

cpe:2.3:a:phpbb:phpbb:*:*:*:*:*:*:*:*

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