CVE-2015-1820: REST client for Ruby (aka rest-client) before 1.8.0 allows remote attackers to conduct session fixation attack

Q: How do I fix CVE-2015-1820?

rest-client: upgrade to newer than 1.7.3. Exact commands for each OS are on this page.

Q: Is CVE-2015-1820 being exploited?

CVE-2015-1820 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2015-1820 affect?

CVE-2015-1820 affects rest-client. Severity is critical (CVSS 9.8). REST client for Ruby (aka rest-client) before 1.8.0 allows remote attackers to conduct session fixation attacks or obtain sensitive cookie information by leveraging passage of cookies set in a response to a redirect.

Q: How urgent is CVE-2015-1820?

Priority 62/100. Critical severity; EPSS top 9%: very likely to be exploited; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2015-1820 is a critical-severity flaw (CVSS 9.8) affecting rest-client. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

REST client for Ruby (aka rest-client) before 1.8.0 allows remote attackers to conduct session fixation attacks or obtain sensitive cookie information by leveraging passage of cookies set in a response to a redirect.

Why this priority

Critical severity
EPSS top 9%: very likely to be exploited
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	4.3% (top 9%)
CISA exploited list	No
Weakness	CWE-384
Published	2017-08-09
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: rest-client project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2017-08-09 18:29 UTCPublished CVE record published
2026-06-17 00:23 UTCUpdated Record last modified

rest-client project rest-client UPGRADE

Affected: <= 1.7.3

Fixed in: newer than 1.7.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy rest-client || rpm -q rest-client || rest-client --version

2. UPGRADE to newer than 1.7.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade rest-client

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade rest-client

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2015-1820?

rest-client: upgrade to newer than 1.7.3. Exact commands for each OS are on this page.

Is CVE-2015-1820 being exploited?

CVE-2015-1820 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2015-1820 affect?

CVE-2015-1820 affects rest-client. Severity is critical (CVSS 9.8). REST client for Ruby (aka rest-client) before 1.8.0 allows remote attackers to conduct session fixation attacks or obtain sensitive cookie information by leveraging passage of cookies set in a response to a redirect.

How urgent is CVE-2015-1820?

Priority 62/100. Critical severity; EPSS top 9%: very likely to be exploited; Remotely exploitable, no login, no user action

Software pages

Ruby vulnerabilities

Related CVEs

CVE-2019-15224 CRITICAL 9.8 UPGRADE The rest-client gem 1.6.10 through 1.6.13 for Ruby, as distributed on RubyGems.org, included a code-execution

References

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