CVE-2020-9548 — Deserialization of Untrusted Data in Debian Debian Linux

Triage

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

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.

Remediation

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

• Documented patch — github.com (NIST National Vulnerability Database)
• Documented patch — www.oracle.com (NIST National Vulnerability Database)
• Documented patch — www.oracle.com (NIST National Vulnerability Database)
• Documented patch — www.oracle.com (NIST National Vulnerability Database)

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 (Debian Debian Linux, Fasterxml Jackson-databind, Netapp Active Iq Unified Manager…).
2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
3. Apply the fixed version or the patch documented under Remediation.
4. EPSS ahead of 97% of scored CVEs: prioritize it in the patch queue.
5. Search available logs for exploit probes matching the vulnerability class (insecure deserialization), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

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

Every base score collected

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

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-502 · Deserialization of Untrusted Data

Other CVEs with this weakness →

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 18.92%

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).
• Monitor serialized objects in requests and unexpected processes spawned by the runtime.

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
• Fix documented
  Oct 13, 2026 · NIST National Vulnerability Database
• CVSS changed · 9.8
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · → Modified
  Oct 13, 2026 · NIST National Vulnerability Database
• Record created in this database
  Oct 13, 2026 · NIST National Vulnerability Database
• 2020
• CVE published
  Mar 2, 2020 · mitre

Source activity

Repeated readings are counted rather than listed.

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

References

16 on the record

• github.com/FasterXML/jackson-databind/issues/2634
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpuoct2020.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpujan2021.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpuoct2021.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• lists.apache.org/thread.html/rd5a4457be4623038c3989294429bc063eec433a2e55995d81591e2ca
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.debian.org/debian-lts-announce/2020/03/msg00008.html
  Mailing List, Third Party Advisory, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.apache.org/thread.html/rdd49ab9565bec436a896bc00c4b9fc9dce1598e106c318524fbdfec6
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• security.netapp.com/advisory/ntap-20200904-0006/
  Third Party Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• lists.apache.org/thread.html/r35d30db00440ef63b791c4b7f7acb036e14d4a23afa2a249cb66c0fd
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpujul2020.html
  Mailing List, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• lists.apache.org/thread.html/rb6fecb5e96a6d61e175ff49f33f2713798dd05cf03067c169d195596
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.apache.org/thread.html/rf1bbc0ea4a9f014cf94df9a12a6477d24a27f52741dbc87f2fd52ff2
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.apache.org/thread.html/r98c9b6e4c9e17792e2cd1ec3e4aa20b61a791939046d3f10888176bb
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.apache.org/thread.html/rdd4df698d5d8e635144d2994922bf0842e933809eae259521f3b5097
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• medium.com/%40cowtowncoder/on-jackson-cves-dont-panic-here-is-what-you-need-to-k
  x_refsource_MISC, NIST National Vulnerability Database
• lists.apache.org/thread.html/r9464a40d25c3ba1a55622db72f113eb494a889656962d098c70c5bb1
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database

Elsewhere on this site

Related CVEs (same products)

• High CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
• Medium CVE-2026-54518 jackson-databind: @JsonView bypass for unwrapped creator parameters in jackson-databind Jun 23, 2026
• Medium CVE-2026-54514 jackson-databind: InetSocketAddress deserialization triggers eager DNS resolution (SSRF) Jun 23, 2026
• High CVE-2026-54512 jackson-databind: PolymorphicTypeValidator bypass via generic type parameters allows arbitrary class instantiation Jun 23, 2026
• High CVE-2026-54513 jackson-databind: Array subtype allowlist bypass in BasicPolymorphicTypeValidator (allowIfSubTypeIsArray) Jun 23, 2026
• Medium CVE-2026-54515 jackson-databind: Case-insensitive deserialization bypasses per-property @JsonIgnoreProperties Jun 23, 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 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-2020-9548 is "Deserialization of Untrusted Data in Debian Debian Linux", rated Critical. It affects Debian Linux (Debian); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.8 describes technical severity. EPSS 18.92% 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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