CVE-2026-44325: free5gc Input Validation Flaw — Exploit

Description

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NRF root SBI endpoint POST /oauth2/token contains a parser-level type-confusion bug family. The handler in NFs/nrf/internal/sbi/api_accesstoken.go reflects over models.NrfAccessTokenAccessTokenReq, special-cases only plain string and NrfNfManagementNfType fields, and treats every other field as if it were a single models.PlmnId. The parsed *models.PlmnId is then assigned with reflect.Value.Set() to whichever field name the attacker put in the form body, which panics whenever the destination field's real type is incompatible (slice, different struct, primitive). Gin recovery converts each panic into HTTP 500, but the endpoint remains remotely panicable from a single unauthenticated form-encoded request and is repeatedly triggerable. This vulnerability is fixed in 4.2.2.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0036

Probability of exploitation

0.28%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-20 Improper Input Validation

CWE-755 CWE-755

CWE-843 CWE-843

Affected Products

Vendor	Product	Versions
free5gc	free5gc	< 4.2.2

References

Advisories & Patches

https://github.com/free5gc/free5gc/security/advisories/GHSA-f8qv-7x5w-qr48 https://github.com/free5gc/nrf/commit/f7bc77daa7425506af7569f2e61c2a210f5a0423 https://github.com/free5gc/nrf/pull/83 https://github.com/free5gc/free5gc/security/advisories/GHSA-f8qv-7x5w-qr48

Exploits

https://github.com/free5gc/free5gc/issues/918 https://github.com/free5gc/free5gc/security/advisories/GHSA-f8qv-7x5w-qr48 https://github.com/free5gc/free5gc/security/advisories/GHSA-f8qv-7x5w-qr48

Frequently Asked Questions

What is CVE-2026-44325? +

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NRF root SBI endpoint POST /oauth2/token contains a parser-level type-confusion bug family. The handler in NFs/nrf/internal/sbi/api_accesstoken.go reflects over models.NrfAccessTokenAccessTokenReq, special-cases only plain string and NrfNfManagementNfType fields, and treats every other field as if it were a single models.PlmnId. The parsed *models.PlmnId is then assigned with reflect.Value.Set() to whichever field name the attacker put in the form body, which panics whenever the destination field's real type is incompatible (slice, different struct, primitive). Gin recovery converts each panic into HTTP 500, but the endpoint remains remotely panicable from a single unauthenticated form-encoded request and is repeatedly triggerable. This vulnerability is fixed in 4.2.2. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-44325? +

CVE-2026-44325 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0036, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-44325? +

CVE-2026-44325 affects products from free5gc, specifically: free5gc. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-44325? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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