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CVE-2026-16615

Librest: weak random number generation in pkce implementation

6.8 MediumFix available

CVE-2026-16615 is a medium vulnerability (CVSS 6.8) in Gnome Librest, published July 22, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. Fixed in rest 0.9.1-11.el10_2.1.

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
None

Exploit likelihood

0.43%Unchanged since Jul 23, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.8

Librest: weak random number generation in pkce implementation

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.

Record
CVE-2026-16615
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-338
Updated
2026-11-02
EUVDEUVD-2026-47742 6.8

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.

Record
EUVD-2026-47742
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-223h-642r-2f6v 6.8

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand...

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.

Record
GHSA-223h-642r-2f6v
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-338
Updated
2026-11-02
NVD 6.8

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.

Record
CVE-2026-16615
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-338
Updated
2026-11-02
OSVDEBIAN-CVE-2026-16615 6.8

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.

Record
DEBIAN-CVE-2026-16615
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVOESA-2026-3974 6.8

rest security update

This library has been designed to make it easier to access web services that claim to be "RESTful". It comprises of two parts: the first aims to make it easier to make requests by providing a wrapper around libsoup, the second aids with XML parsing by wrapping libxml2.

Security Fix(es):

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.(CVE-2026-16615)

Record
OESA-2026-3974
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
Show 16 moreShow less
OSVOESA-2026-3975 6.8

rest security update

This library has been designed to make it easier to access web services that claim to be "RESTful". It comprises of two parts: the first aims to make it easier to make requests by providing a wrapper around libsoup, the second aids with XML parsing by wrapping libxml2.

Security Fix(es):

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.(CVE-2026-16615)

Record
OESA-2026-3975
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVOESA-2026-3976 6.8

rest security update

This library has been designed to make it easier to access web services that claim to be "RESTful". It comprises of two parts: the first aims to make it easier to make requests by providing a wrapper around libsoup, the second aids with XML parsing by wrapping libxml2.

Security Fix(es):

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.(CVE-2026-16615)

Record
OESA-2026-3976
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVRHSA-2026:47085 6.8

Red Hat Security Advisory: rest security update

Record
RHSA-2026:47085
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVRHSA-2026:62222 6.8

Red Hat Security Advisory: rest security update

Record
RHSA-2026:62222
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVRLSA-2026:47085 6.8

Important: rest security update

The rest packages provide a library for access to the RESTful web services.

Security Fix(es):

  • librest: weak random number generation in PKCE implementation (CVE-2026-16615)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Record
RLSA-2026:47085
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVUBUNTU-CVE-2026-16615 6.8

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.

Record
UBUNTU-CVE-2026-16615
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVALSA-2026:47085 No score

Important: rest security update

The rest packages provide a library for access to the RESTful web services.

Security Fix(es):

  • librest: weak random number generation in PKCE implementation (CVE-2026-16615)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Record
ALSA-2026:47085
Updated
2026-11-02
OSVAZL-93303 No score

CVE-2026-16615 affecting package rest for versions less than 0.9.0-2

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.

Record
AZL-93303
Updated
2026-11-02
OSVMGASA-2026-0436 No score

Updated rest packages fix a security vulnerability

Weak random number generation in pkce implementation. (CVE-2026-16615)

Record
MGASA-2026-0436
Updated
2026-11-02
OSVopenSUSE-SU-2026:11477-1 No score

librest-1_0-0-0.10.2-2.1 on GA media

These are all security issues fixed in the librest-1_0-0-0.10.2-2.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:11477-1
Updated
2026-11-02
OSVopenSUSE-SU-2026:21563-1 No score

Security update for librest0_7

This update for librest0_7 fixes the following issues:

Changes in librest0_7:

  • CVE-2026-16615: Fix weak random number generation (bsc#1272399, glgo#GNOME/librest!44).
Record
openSUSE-SU-2026:21563-1
Updated
2026-11-02
OSVopenSUSE-SU-2026:21694-1 No score

Security update for librest

This update for librest fixes the following issue:

  • CVE-2026-16615: PKCE implementation for OAuth authorization uses a cryptographically insecure pseudo-random number generator (bsc#1272399).
Record
openSUSE-SU-2026:21694-1
Updated
2026-11-02
OSVSUSE-SU-2026:23564-1 No score

Security update for librest

This update for librest fixes the following issue:

  • CVE-2026-16615: PKCE implementation for OAuth authorization uses a cryptographically insecure pseudo-random number generator (bsc#1272399).
Record
SUSE-SU-2026:23564-1
Updated
2026-11-02
OSVSUSE-SU-2026:3795-1 No score

Security update for librest

This update for librest fixes the following issue:

  • CVE-2026-16615: PKCE implementation for OAuth authorization uses a cryptographically insecure pseudo-random number generator (bsc#1272399).
Record
SUSE-SU-2026:3795-1
Updated
2026-11-02
OSVSUSE-SU-2026:3796-1 No score

Security update for librest

This update for librest fixes the following issue:

  • CVE-2026-16615: PKCE implementation for OAuth authorization uses a cryptographically insecure pseudo-random number generator (bsc#1272399).
Record
SUSE-SU-2026:3796-1
Updated
2026-11-02
OSVSUSE-SU-2026:3834-1 No score

Security update for librest0_7

This update for librest0_7 fixes the following issue:

  • CVE-2026-16615: PKCE implementation for OAuth authorization uses a cryptographically insecure pseudo-random number generator (bsc#1272399).
Record
SUSE-SU-2026:3834-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
rest
AlmaLinux:10
 before 0.9.1-11.el10_2.1
0.9.1-11.el10_2.1
rest-devel
AlmaLinux:10
 before 0.9.1-11.el10_2.1
0.9.1-11.el10_2.1
rest
Azure Linux:3
 before 0.9.0-2
0.9.0-2
librest
Debian:12
 All versions, plus listed versions
0.10.2-10.9.1-61.0.0-1
 None known
librest
Debian:13
 All versions, plus listed versions
0.10.2-10.9.1-61.0.0-1
 None known
librest
Debian:14
 All versions, plus listed versions
0.10.2-10.9.1-61.0.0-1
 None known
rest
Mageia:10
 before 0.10.2-2.1.mga10
0.10.2-2.1.mga10
rest
Mageia:9
 before 0.9.1-2.1.mga9
0.9.1-2.1.mga9
rest
openEuler:24.03-LTS-SP1
 before 0.9.1-6.oe2403sp1
0.9.1-6.oe2403sp1
rest
openEuler:24.03-LTS-SP3
 before 0.9.1-6.oe2403sp3
0.9.1-6.oe2403sp3
Show 27 moreShow less
Affected packages
PackageAffectedFixed
rest
openEuler:24.03-LTS-SP4
 before 0.9.1-6.oe2403sp4
0.9.1-6.oe2403sp4
rest
Red Hat:enterprise_linux:10.2
 before 0:0.9.1-11.el10_2.1
0:0.9.1-11.el10_2.1
rest-debuginfo
Red Hat:enterprise_linux:10.2
 before 0:0.9.1-11.el10_2.1
0:0.9.1-11.el10_2.1
rest-debugsource
Red Hat:enterprise_linux:10.2
 before 0:0.9.1-11.el10_2.1
0:0.9.1-11.el10_2.1
rest-demo-debuginfo
Red Hat:enterprise_linux:10.2
 before 0:0.9.1-11.el10_2.1
0:0.9.1-11.el10_2.1
rest-devel
Red Hat:enterprise_linux:10.2
 before 0:0.9.1-11.el10_2.1
0:0.9.1-11.el10_2.1
rest
Red Hat:enterprise_linux_eus:10.0
 before 0:0.9.1-11.el10_0.1
0:0.9.1-11.el10_0.1
rest-debuginfo
Red Hat:enterprise_linux_eus:10.0
 before 0:0.9.1-11.el10_0.1
0:0.9.1-11.el10_0.1
rest-debugsource
Red Hat:enterprise_linux_eus:10.0
 before 0:0.9.1-11.el10_0.1
0:0.9.1-11.el10_0.1
rest-demo-debuginfo
Red Hat:enterprise_linux_eus:10.0
 before 0:0.9.1-11.el10_0.1
0:0.9.1-11.el10_0.1
rest-devel
Red Hat:enterprise_linux_eus:10.0
 before 0:0.9.1-11.el10_0.1
0:0.9.1-11.el10_0.1
rest
Rocky Linux:10
 before 0:0.9.1-11.el10_2.1
0:0.9.1-11.el10_2.1
librest
SUSE:Linux Enterprise Server 16.0
 before 0.9.1-160000.3.1
0.9.1-160000.3.1
librest
SUSE:Linux Enterprise Server for SAP applications 16.0
 before 0.9.1-160000.3.1
0.9.1-160000.3.1
librest
SUSE:Linux Enterprise Module for Desktop Applications 15 SP7
 before 0.9.1-150600.3.3.1
0.9.1-150600.3.3.1
librest
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5
 before 0.8.0-13.3.1
0.8.0-13.3.1
librest0_7
SUSE:Linux Enterprise Workstation Extension 15 SP7
 before 0.8.1-150600.4.3.1
0.8.1-150600.4.3.1
librest
Ubuntu:16.04:LTS
 All versions, plus listed versions
0.7.93-1
 None known
librest
Ubuntu:18.04:LTS
 All versions, plus listed versions
0.8.0-2
 None known
librest
Ubuntu:20.04:LTS
 All versions, plus listed versions
0.8.1-1
 None known
librest
Ubuntu:22.04:LTS
 All versions, plus listed versions
0.8.1-1.1build10.8.1-1.1build2
 None known
librest
Ubuntu:24.04:LTS
 All versions, plus listed versions
0.9.1-60.9.1-6build20.9.1-6build3
 None known
librest
Ubuntu:26.10
 All versions, plus listed versions
0.10.2-1
 None known
librest
Ubuntu:26.04:LTS
 All versions, plus listed versions
0.9.1-6build40.10.2-1
 None known
librest
openSUSE:Tumbleweed
 before 0.10.2-2.1
0.10.2-2.1
librest0_7
openSUSE:Leap 16.0
 before 0.8.1-bp160.2.1
0.8.1-bp160.2.1
librest
openSUSE:Leap 16.0
 before 0.9.1-160000.3.1
0.9.1-160000.3.1

History

History
WhenChangedSources
2026-11-02createdCVE List, EUVD, GitHub Advisories, NVD, OSV

References

Show 22 moreShow less
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