Public proof of conceptFix available

CVE-2018-1000844

Q: Is CVE-2018-1000844 actively exploited?

Active exploitation of CVE-2018-1000844 has not been confirmed. Its EPSS score was 2.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2018-1000844?

CVE-2018-1000844 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

A public proof of concept exists; no exploitation attested.

Published2018-12-20
Fixed in2.5.0
WeaknessCWE-611

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Square Open Source Retrofit version Prior to commit 4a693c5aeeef2be6c7ecf80e7b5ec79f6ab59437 contains a XML External Entity (XXE) vulnerability in JAXB that can result in An attacker could use this to remotely read files from the file system or to perform SSRF.. This vulnerability appears to have been fixed in After commit 4a693c5aeeef2be6c7ecf80e7b5ec79f6ab59437.

Timeline

dates in UTC

2018-12-2015:29CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2018-1000844?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2018-1000844?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Squareup retrofit

Branch	Affected	Fixed in	Source
2.x	≥ 2.4.0, < 2.5.0	2.5.0	NVD
2.x	≥ 2.0.0, < 2.5.0	2.5.0	OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Squareup retrofit to 2.5.0

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifiedepicosy/Retrofit-1

Sources

NVDCVSS 3.09.1read 2026-10-23
NVDCVSS 2.06.4read 2026-10-23
NVDweakness (CWE)CWE-611read 2026-10-23
FIRST EPSSEPSS score2.2 %2026-10-23
PoC-in-GitHubproof of concept1read 2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Published: 2018-12-20
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2018-1000844?

Is CVE-2018-1000844 actively exploited?

Active exploitation of CVE-2018-1000844 has not been confirmed. Its EPSS score was 2.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-1000844?

CVE-2018-1000844 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

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