How severe is CVE-2025-47917?

CVE-2025-47917 has a CVSS 3.x base score of 8.9, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability high.

Is CVE-2025-47917 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-47917?

CVE-2025-47917 affects Arm Mbed Tls. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-47917?

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-2025-47917 have an EU (EUVD) identifier?

Yes. CVE-2025-47917 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-22035.

When was CVE-2025-47917 published?

CVE-2025-47917 was published on 2025-07-20 and last updated on 2026-06-17.

CVE-2025-47917

CVE-2025-47917 is a high-severity vulnerability in Arm Mbed Tls with a CVSS 3.x base score of 8.9. 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-416.

Key facts

Severity: High (CVSS 3.x base score 8.9)
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-22035
Weakness: CWE-416
Affected product: Arm Mbed Tls
Published: 2025-07-20
Last modified: 2026-06-17

Description

Mbed TLS before 3.6.4 allows a use-after-free in certain situations of applications that are developed in accordance with the documentation. The function mbedtls_x509_string_to_names() takes a head argument that is documented as an output argument. The documentation does not suggest that the function will free that pointer; however, the function does call mbedtls_asn1_free_named_data_list() on that argument, which performs a deep free(). As a result, application code that uses this function (relying only on documented behavior) is likely to still hold pointers to the memory blocks that were freed, resulting in a high risk of use-after-free or double-free. In particular, the two sample programs x509/cert_write and x509/cert_req are affected (use-after-free if the san string contains more than one DN).

Frequently asked questions

What is CVE-2025-47917?: Mbed TLS before 3.6.4 allows a use-after-free in certain situations of applications that are developed in accordance with the documentation. The function mbedtls_x509_string_to_names() takes a head argument that is documented as an output argument. The documentation does not suggest that the function will free that pointer; however, the function does call mbedtls_asn1_free_named_data_list() on that argument, which performs a deep free(). As a result, application code that uses this function (relying only on documented behavior) is likely to still hold pointers to the memory blocks that were freed, resulting in a high risk of use-after-free or double-free. In particular, the two sample programs x509/cert_write and x509/cert_req are affected (use-after-free if the san string contains more than one DN).
How severe is CVE-2025-47917?: CVE-2025-47917 has a CVSS 3.x base score of 8.9, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability high.
Is CVE-2025-47917 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-47917?: CVE-2025-47917 affects Arm Mbed Tls. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-47917?: 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-2025-47917 have an EU (EUVD) identifier?: Yes. CVE-2025-47917 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-22035.
When was CVE-2025-47917 published?: CVE-2025-47917 was published on 2025-07-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*

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