CVE Intelligence
Critical Insecure deserialization

CVE-2020-8840 — Deserialization of Untrusted Data in Debian Debian Linux

FasterXML jackson-databind 2.0.0 through 2.9.10.2 lacks certain xbean-reflect/JNDI blocking, as demonstrated by org.apache.xbean.propertyeditor.JndiConverter.

Published Feb 10, 2020 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: mitre

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 26.6% (30-day exploitation probability)+15
  • Technical severity (critical)+10
  • 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
26.59%
ahead of 98% of scored CVEs · Oct 14, 2026
Affects
Debian
Debian Linux and 7 more
CVSS base
9.8
Critical · 1 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
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Total
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 (Debian Debian Linux, Fasterxml Jackson-databind, Huawei Oceanstor 9000 Firmware…).
  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. EPSS ahead of 98% 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.

VendorProductVersionsStatusSource
Debian Debian Linux version 8.0 Vulnerable NIST National Vulnerability Database
Fasterxml Jackson-databind ≥ 2.0.0 and < 2.7.9.7≥ 2.8.0 and < 2.8.11.5≥ 2.9.0 and < 2.9.10.3 Vulnerable NIST National Vulnerability Database
Huawei Oceanstor 9000 Firmware version v300r006c20version v300r006c20spc100version v300r006c20spc200version v300r006c20spc300 Vulnerable NIST National Vulnerability Database
Netapp Oncommand Api Services versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Oncommand Workflow Automation versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Service Level Manager versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Steelstore Cloud Integrated Storage versions not specified by the source Vulnerable NIST National Vulnerability Database
Oracle Global Lifecycle Management Opatch < 11.2.0.3.23≥ 12.2.0.1.0 and < 12.2.0.1.19≥ 13.9.4.0.0 and < 13.9.4.2.1 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
High
Integrity
High
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
9.8 CVSS 3.1 Critical 3.9 5.9 nvd@nist.gov via NIST National Vulnerability Database
7.5 CVSS 2.0 High 10.0 6.4 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-502 · Deserialization of Untrusted Data

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 26.59%

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.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)application logs

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 · 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
    Feb 10, 2020 · mitre

Source activity

Repeated readings are counted rather than listed.

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

References

44 on the record

Elsewhere on this site

Debian
every CVE for this vendor
Insecure deserialization
same class
CWE-502
other pages naming this weakness

Related CVEs (same products)

  • 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
  • CVE-2026-59888 jackson-databind: @JsonIgnore on a Record property is bypassed with a PropertyNamingStrategy Jul 14, 2026
  • CVE-2026-14355 ext/openssl: Memory corruption in openssl_encrypt with AES-WRAP-PAD Jul 3, 2026
  • CVE-2026-54518 jackson-databind: @JsonView bypass for unwrapped creator parameters in jackson-databind Jun 23, 2026
  • CVE-2026-54515 jackson-databind: Case-insensitive deserialization bypasses per-property @JsonIgnoreProperties Jun 23, 2026
  • CVE-2026-54517 jackson-databind: @JsonView bypass for setterless creator properties 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 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-2020-8840 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 26.59% 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.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.