How severe is CVE-2021-29476?

CVE-2021-29476 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-29476 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-29476?

CVE-2021-29476 primarily affects Wordpress Requests. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-29476?

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

When was CVE-2021-29476 published?

CVE-2021-29476 was published on 2021-04-27 and last updated on 2026-06-17.

CVE-2021-29476

CVE-2021-29476 is a critical-severity vulnerability in Wordpress Requests with a CVSS 3.x base score of 9.8. 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-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Wordpress Requests
Published: 2021-04-27
Last modified: 2026-06-17

Description

Requests is a HTTP library written in PHP. Requests mishandles deserialization in FilteredIterator. The issue has been patched and users of `Requests` 1.6.0, 1.6.1 and 1.7.0 should update to version 1.8.0.

Frequently asked questions

What is CVE-2021-29476?: Requests is a HTTP library written in PHP. Requests mishandles deserialization in FilteredIterator. The issue has been patched and users of `Requests` 1.6.0, 1.6.1 and 1.7.0 should update to version 1.8.0.
How severe is CVE-2021-29476?: CVE-2021-29476 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-29476 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-29476?: CVE-2021-29476 primarily affects Wordpress Requests. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-29476?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-29476 published?: CVE-2021-29476 was published on 2021-04-27 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:wordpress:requests:1.6.0:*:*:*:*:*:*:*
cpe:2.3:a:wordpress:requests:1.6.1:*:*:*:*:*:*:*
cpe:2.3:a:wordpress:requests:1.7.0:*:*:*:*:*:*:*

Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities

CVE-2026-70416 — Critical (CVSS 10.0): Dell ObjectScale, versions prior to 4.4.0.0, contains a Deserialization of Untrusted Data vulnerability. An…
CVE-2026-82222 — Critical (CVSS 10.0): Deserialization of Untrusted Data vulnerability in Liquid Web / StellarWP GiveWP allows Object Injection. This issue…
CVE-2026-69836 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Entra ID allows an unauthorized attacker to execute code over a network.
CVE-2026-17061 — Critical (CVSS 10.0): A Deserialization of Untrusted Data vulnerability affecting SIMULIA Execution Engine from Release 2023 through Release…
CVE-2026-11756 — Critical (CVSS 10.0): A Deserialization of Untrusted Data vulnerability affecting Station Launcher App in 3DEXPERIENCE platform from Release…
CVE-2026-41104 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Planetary Computer Pro allows an unauthorized attacker to disclose…

Browse all CWE-502 (Deserialization of Untrusted Data) vulnerabilities →