How severe is CVE-2025-6491?

CVE-2025-6491 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-6491 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-6491?

CVE-2025-6491 affects Php. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-6491?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-6491 have an EU (EUVD) identifier?

Yes. CVE-2025-6491 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21276.

When was CVE-2025-6491 published?

CVE-2025-6491 was published on 2025-07-13 and last updated on 2026-06-17.

CVE-2025-6491

CVE-2025-6491 is a medium-severity vulnerability in Php with a CVSS 3.x base score of 5.9. 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-476.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 1% (57th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-21276
Weakness: CWE-476
Affected product: Php
Published: 2025-07-13
Last modified: 2026-06-17

Description

In PHP versions:8.1.* before 8.1.33, 8.2.* before 8.2.29, 8.3.* before 8.3.23, 8.4.* before 8.4.10 when parsing XML data in SOAP extensions, overly large (>2Gb) XML namespace prefix may lead to null pointer dereference. This may lead to crashes and affect the availability of the target server.

Frequently asked questions

What is CVE-2025-6491?: In PHP versions:8.1.* before 8.1.33, 8.2.* before 8.2.29, 8.3.* before 8.3.23, 8.4.* before 8.4.10 when parsing XML data in SOAP extensions, overly large (>2Gb) XML namespace prefix may lead to null pointer dereference. This may lead to crashes and affect the availability of the target server.
How severe is CVE-2025-6491?: CVE-2025-6491 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-6491 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-6491?: CVE-2025-6491 affects Php. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-6491?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-6491 have an EU (EUVD) identifier?: Yes. CVE-2025-6491 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21276.
When was CVE-2025-6491 published?: CVE-2025-6491 was published on 2025-07-13 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:php:php:*:*:*:*:*:*:*:*

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Other CWE-476 (NULL Pointer Dereference) vulnerabilities

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CVE-2010-2495 — Critical (CVSS 10.0): The pppol2tp_xmit function in drivers/net/pppol2tp.c in the L2TP implementation in the Linux kernel before 2.6.34 does…
CVE-2026-46195 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building…
CVE-2026-31657 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by…
CVE-2026-31436 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: fix possible wrong descriptor…

Browse all CWE-476 (NULL Pointer Dereference) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

41.205.23.59 (ipv4-addr)
146.190.83.66 (ipv4-addr)
152.89.64.17 (ipv4-addr)
82.39.35.211 (ipv4-addr)
45.177.210.193 (ipv4-addr)
39.164.91.67 (ipv4-addr)
122.3.106.113 (ipv4-addr)
23.95.137.106 (ipv4-addr)