CVE Intelligence
High Memory corruption exploit reference

CVE-2026-1976 — Free5GC SMF SessionDeletionResponse null pointer dereference

A weakness has been identified in Free5GC up to 4.1.0. Affected is the function SessionDeletionResponse of the component SMF. This manipulation causes null pointer dereference. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks. It is suggested to install a patch to address this issue.

Published Feb 6, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: VulDB

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.6% (30-day exploitation probability)+7
  • Technical severity (high)+6
  • CISA SSVC: exploitation "poc"+5
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.61%
ahead of 48% of scored CVEs · Oct 14, 2026
Affects
Free5gc
Free5gc
CVSS base
7.5
High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Free5gc Free5gc).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Free5gc Free5gc ≤ 4.1.0 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
6.9 CVSS 4.0 Medium — — VulDB via CVE Program (cve.org) e CISA ADP
5.5 CVSS 4.0 Medium — — cna@vuldb.com via NIST National Vulnerability Database
7.5 CVSS 3.1 High 3.9 3.6 nvd@nist.gov via NIST National Vulnerability Database
5.3 CVSS 3.1 Medium 3.9 1.4 cna@vuldb.com via NIST National Vulnerability Database
5.3 CVSS 3.1 Medium — — VulDB via CVE Program (cve.org) e CISA ADP
5.3 CVSS 3.0 Medium — — VulDB via CVE Program (cve.org) e CISA ADP
5.0 CVSS 2.0 Medium 10.0 2.9 cna@vuldb.com via NIST National Vulnerability Database
5.0 CVSS 2.0 Medium — — VulDB via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)
Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 7.5 (NVD (NIST)) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-476 · NULL Pointer Dereference

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.61%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 7.5
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Feb 6, 2026 · VulDB

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

7 on the record

Elsewhere on this site

Free5gc
every CVE for this vendor
Memory corruption
same class
CWE-476
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-44330 free5GC: NEF nnef-pfdmanagement API is unauthenticated; forged bearer tokens can read PFD data and create/delete PFD subscriptions May 27, 2026
  • CVE-2026-44326 free5GC: NEF 3gpp-traffic-influence API is unauthenticated; missing or forged bearer tokens can create, read, patch, and delete subscriptions May 27, 2026
  • CVE-2026-44327 free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler May 27, 2026
  • CVE-2026-44328 free5GC: SMF UPI DELETE /upi/v1/upNodesLinks/{ref} panics on AN-node deletion via nil UPF dereference; unauthenticated, state-mutating May 27, 2026
  • CVE-2026-44329 free5GC: SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers May 27, 2026
  • CVE-2026-44320 free5GC: NEF nnef-callback route group is unauthenticated; forged callback requests are accepted into the processing path May 27, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-1976 is "Free5GC SMF SessionDeletionResponse null pointer dereference", rated High. It affects Free5gc (Free5gc); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.61% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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