CVE-2026-42459: free5GC: Improper Input Validation and Generation of Error Message Containing Sensitive Information in github.com/free5gc/udm
Vulnerability summary
CVE-2026-42459 is a high (CVSS 7.7) Improper Input Validation vulnerability in free5gc. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 37.9% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 27-05-2026PublishedVulnerability first disclosed.
- 28-05-2026Last modifiedVulnerability information updated.
Description
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, the free5GC UDM component fails to validate the supi path parameter in six GET handlers of the nudm-sdm (Subscriber Data Management) service. An unauthenticated attacker can inject control characters into the SUPI parameter, causing UDM to forward a malformed request to UDR and return a 500 Internal Server Error response that exposes internal infrastructure details. This vulnerability is fixed in 4.2.2.
CVSS metrics
5 scores · 3 sources · 2 versions- OSV · GoEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:PDiffers
- NVDNIST7.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS trend
Probability
0.45%
Chance of exploitation in the next 30 days
Percentile
38%
Versus all other CVEs
30-day change
Increase +0.12 pp
From 0.32% on 22-09-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundFree5Gc
Maturity: poc
Weaknesses
CWE · root cause- CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- CWE-209Generation of Error Message Containing Sensitive InformationThe product generates an error message that includes sensitive information about its environment, users, or associated data.
Affected systems
Free5gc1 product
- free5gc< 4.2.2
Github.com/free5gc1 product
- udm≤ 1.4.3 | All versions (No fix recorded)
2 vendors · 2 products
References
5 links- github.com/free5gc/free5gc/security/advisories/GHSA-585v-hcgf-jhfrX Refsource CONFIRMWEBAdvisoryExploitMitigationVendor Advisory
- github.com/free5gc/free5gcPACKAGE