CVE-2020-26259 | XStream is vulnerable to an Arbitrary File Deletion on the local host when unmarshalling

Exp

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.15, is vulnerable to an Arbitrary File Deletion on the local host when unmarshalling. The vulnerability may allow a remote attacker to delete arbitrary know files on the host as log as the executing process has sufficient rights only by manipulating the processed input stream. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.15. The reported vulnerability does not exist running Java 15 or higher. No user is affected, who followed the recommendation to setup XStream's Security Framework with a whitelist! Anyone relying on XStream's default blacklist can immediately switch to a whilelist for the allowed types to avoid the vulnerability. Users of XStream 1.4.14 or below who still want to use XStream default blacklist can use a workaround described in more detailed in the referenced advisories.

Published: 2020-12-16 Last update: 2025-05-23 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-26259 is rated High Exploit Risk (75.2/100): CVSS Medium severity, with high exploitation likelihood (EPSS 88.87%, 100th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2020-26259

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2020-26259

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-01-03 90.70% 88.87% -1.83%
2 2025-12-28 91.44% 90.70% -0.73%
3 2025-12-27 — 91.44% —

Full EPSS history (27 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-26259

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 4.0 [email protected]
6.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 4.0 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2020-26259

GitHub Security Advisory for CVE-2020-26259

GHSA-jfvx-7wrx-43fh · Severity: medium · Ecosystem: maven — XStream vulnerable to an Arbitrary File Deletion on the local host when unmarshalling

OS Trackers for CVE-2020-26259

vendor priority summary link
debian not yet assigned CVE-2020-26259 not yet assigned priority: Debian including 1 source packages (libxstream-java), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-26259
redhat medium — https://access.redhat.com/security/cve/CVE-2020-26259
suse medium CVE-2020-26259 severity moderate: SUSE including 303 source package names (5.0.0-beta1.2.122:xpp3-1.1.4c-11.2.2, 5.0.0-beta1.2.122:xpp3-minimal-1.1.4c-11.2.2, …), 373 product×package rows across 30 product lines (Container suse/manager/5.0/x86_64/server, Container suse/multi-linux-manager/5.1/x86_64/server, … (30 product lines)): Known Affected 231, Fixed 142. https://www.suse.com/security/cve/CVE-2020-26259/
ubuntu medium CVE-2020-26259 medium priority: Ubuntu including 1 source packages (libxstream-java), 14 status rows across 14 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, trusty, upstream, xenial): not-affected 8, released 6. https://ubuntu.com/security/CVE-2020-26259

Affected software / configurations for CVE-2020-26259

Vendor Product Version Raw CPE
apache struts < 6.0.0 cpe:2.3:a:apache:struts:*:*:*:*:*:*:*:*
xstream xstream < 1.4.15 cpe:2.3:a:xstream:xstream:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

References for CVE-2020-26259

URL Tags
https://github.com/x-stream/xstream/security/advisories/GHSA-jfvx-7wrx-43fh Mitigation Third Party Advisory
https://lists.apache.org/thread.html/r97993e3d78e1f5389b7b172ba9f308440830ce5f051ee62714a0aa34%40%3Ccommits.struts.apache.org%3E Issue Tracking Mailing List
https://lists.debian.org/debian-lts-announce/2020/12/msg00042.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/ Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/ Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/ Mailing List
https://security.netapp.com/advisory/ntap-20210409-0005/ Third Party Advisory
https://www.debian.org/security/2021/dsa-4828 Third Party Advisory
https://x-stream.github.io/CVE-2020-26259.html Exploit Mitigation Third Party Advisory
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