VulnerabilityPublished 20 Mar 2026

CVE-2026-32937: free5gc chf · Improper Validation of Array Index

Affects free5gc chfSource CVE Database V5

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Not known to be exploited · CVSS 7.1 High : upgrade to 1.2.2 soon.

Data as of 1 Nov 2026, 08:20 UTC

CVSS 4.0 base score

7.1High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.2.2

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: High
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: High: There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Vulnerable System; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the Vulnerable System (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade chf and github.com/free5gc/chf to 1.2.2.

Affected software

Product	Affected	Fixed in
free5gcchf	Affected <1.2.2	Fixed in 1.2.2
Gogithub.com/free5gc/chf`pkg:golang/github.com/free5gc/chf`Other threats	Affected <1.2.2	Fixed in 1.2.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-32937, organizations should upgrade free5GC CHF to version 1.2.2 or later where the vulnerability is patched. Until upgrading, restrict access to the `/nchf-convergedcharging/v3/recharging/:ueId` endpoint strictly to trusted network functions (NFs) using network segmentation and strong authentication controls. Implement rate limiting on the CHF SBI interface to prevent repeated triggering of the panic condition. Deploy network ACLs or firewall rules to limit exposure of the recharge API to only necessary internal components. If the recharge API is not required in the deployment, disable or block external reachability to this endpoint entirely. Ensure that the Gin recovery middleware or equivalent panic recovery mechanisms are enabled and properly configured to handle runtime panics gracefully, preventing service crashes. Establish monitoring and alerting on CHF service logs and metrics to detect abnormal panic events or service degradation promptly. Conduct regular security audits and penetration testing focused on internal NF interfaces to identify and remediate similar vulnerabilities proactively.

Description

CVE-2026-32937 is a high-severity vulnerability in free5GC's CHF component prior to version 1.2.2, caused by improper validation of array indexes leading to out-of-bounds slice access. An authenticated attacker can trigger a server-side panic via a crafted PUT request to the recharge endpoint, causing service disruption. While some deployments convert this panic into HTTP 500 errors, others may experience more severe outages. The vulnerability can be exploited repeatedly to degrade recharge functionality and flood logs, impacting availability. Mitigations include restricting access to trusted network functions, applying rate limiting, disabling the recharge API if unused, and ensuring panic recovery and monitoring are in place. This vulnerability affects 5G core network deployments using free5GC CHF, particularly in countries with active 5G infrastructure adopting open-source core solutions. The CVSS 4.0 score is 7.

Impact

The primary impact of CVE-2026-32937 is on the availability of the free5GC CHF service, which is responsible for converged charging in 5G core networks. Successful exploitation can cause repeated server panics, leading to degraded recharge functionality and potential denial of service. This can disrupt subscriber charging operations, affecting billing accuracy and potentially causing service interruptions for end users. The flooding of logs may also impact system performance and complicate incident response. In deployments without proper panic recovery, the CHF service could crash entirely, causing more severe outages in the 5G core network. Given the critical role of charging functions in telecom networks, this vulnerability poses a significant risk to network operators relying on free5GC, potentially affecting revenue and customer trust. The vulnerability requires authenticated access, limiting exposure to internal or trusted network functions, but if those are compromised or misconfigured, the risk increases. No known active exploitation reduces immediate risk, but the ease of triggering the panic and the availability impact warrant prompt remediation.

CWE-129Improper Validation of Array Index (opens in a new tab)
Variant weaknessLikelihood of exploit: HighOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.
Architecture and Design · Input Validation
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overflow Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Mar 2026, 19:35 UTC

WeaknessesCWE-129

Technical details

References

Community reviews

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