CVE-2025-70974: FASTJSON Includes Functionality from Untrusted Control Sphere

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.8%, percentile 55: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 55% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes com.alibaba:fastjson (Maven) < 1.2.48, fixed in 1.2.48. Check your lockfile, including transitive dependencies.

What it is

Fastjson before 1.2.48 mishandles autoType because, when an @type key is in a JSON document, and the value of that key is the name of a Java class, there may be calls to certain public methods of that class. Depending on the behavior of those methods, there may be JNDI injection with an attacker-supplied payload located elsewhere in that JSON document. This was exploited in the wild in 2023 through 2025. NOTE: this issue exists because of an incomplete fix for CVE-2017-18349. Also, a later bypass is covered by CVE-2022-25845.

From the GitHub advisory

Fastjson before 1.2.48 mishandles autoType because, when an @type key is in a JSON document, and the value of that key is the name of a Java class, there may be calls to certain public methods of that class. Depending on the behavior of those methods, there may be JNDI injection with an attacker-supplied payload located elsewhere in that JSON document. This was exploited in the wild in 2023 through 2025. NOTE: this issue exists because of an incomplete fix for CVE-2017-18349. Also, a later bypass is covered by CVE-2022-25845.

Weakness type: CWE-829.

Product: com.alibaba:fastjson (Maven) · Assigned by: mitre · Published: 2026-01-09

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.76% probability of exploitation activity in the next 30 days; percentile 55.

Timeline

• 2026-01-09 — CVE record published by mitre
• 2026-01-09 — GitHub-reviewed advisory GHSA-jm7w-5684-pvh8 published (critical)
• 2026-07-15 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-jm7w-5684-pvh8 github.com
2. CVE.org record CVE-2025-70974 cve.org
3. NVD entry CVE-2025-70974 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. seebug.org seebug.org
3. cnvd.org.cn cnvd.org.cn
4. freebuf.com freebuf.com
5. github.com github.com
6. cloudsek.com cloudsek.com
7. cert.360.cn cert.360.cn
8. access.redhat.com access.redhat.com
9. RHBZ#2428203 bugzilla.redhat.com
10. security.access.redhat.com security.access.redhat.com
11. web.archive.org web.archive.org

Critical Maven advisories · Today’s Security Digest