CVE-2017-7186: libpcre1 in PCRE 8.40 and libpcre2 in PCRE2 10.23 allow remote attackers to cause a denial of service (segment

This month

HIGH 7.5REMOTEDOWNGRADEDOWNGRADE

CVE-2017-7186 is a high-severity flaw (CVSS 7.5) affecting pcre, pcre2. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

libpcre1 in PCRE 8.40 and libpcre2 in PCRE2 10.23 allow remote attackers to cause a denial of service (segmentation violation for read access, and application crash) by triggering an invalid Unicode property lookup.

Why this priority

High severity
EPSS top 8%: very likely to be exploited
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	5.0% (top 8%)
CISA exploited list	No
Weakness	CWE-119
Published	2017-03-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: pcre

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

Am I affected?

Timeline

2017-03-20 00:59 UTCPublished CVE record published
2026-06-17 01:23 UTCUpdated Record last modified

pcre pcre DOWNGRADE

Affected: 8.40

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.40

1. Check installed version

apt-cache policy pcre || rpm -q pcre || pcre --version

2. No fixed release: DOWNGRADE to a release before 8.40 (Debian / Ubuntu)

apt-cache madison pcre sudo apt install pcre=<VERSION_BEFORE_8.40> sudo apt-mark hold pcre

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list pcre sudo dnf downgrade pcre-<VERSION_BEFORE_8.40> sudo dnf versionlock add pcre

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

pcre pcre2 DOWNGRADE

Affected: 10.23

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.23

1. Check installed version

apt-cache policy pcre2 || rpm -q pcre2 || pcre2 --version

2. No fixed release: DOWNGRADE to a release before 10.23 (Debian / Ubuntu)

apt-cache madison pcre2 sudo apt install pcre2=<VERSION_BEFORE_10.23> sudo apt-mark hold pcre2

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list pcre2 sudo dnf downgrade pcre2-<VERSION_BEFORE_10.23> sudo dnf versionlock add pcre2

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2017-7186?

pcre: downgrade or apply the listed mitigation; pcre2: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2017-7186 being exploited?

CVE-2017-7186 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-2017-7186 affect?

CVE-2017-7186 affects pcre, pcre2. Severity is high (CVSS 7.5). libpcre1 in PCRE 8.40 and libpcre2 in PCRE2 10.23 allow remote attackers to cause a denial of service (segmentation violation for read access, and application crash) by triggering an invalid Unicode property lookup.

How urgent is CVE-2017-7186?

Priority 54/100. High severity; EPSS top 8%: very likely to be exploited; Remotely exploitable, no login, no user action

Related CVEs

CVE-2019-20838 HIGH 7.5 UPGRADE UPGRADE libpcre in PCRE before 8.43 allows a subject buffer over-read in JIT when UTF is disabled, and \X or \R has mo
CVE-2020-14155 MEDIUM 5.3 UPGRADE UPGRADE libpcre in PCRE before 8.44 allows an integer overflow via a large number after a (?C substring.
CVE-2017-7246 HIGH 7.8 DOWNGRADE Stack-based buffer overflow in the pcre32_copy_substring function in pcre_get.c in libpcre1 in PCRE 8.40 allow
CVE-2017-7245 HIGH 7.8 DOWNGRADE Stack-based buffer overflow in the pcre32_copy_substring function in pcre_get.c in libpcre1 in PCRE 8.40 allow
CVE-2017-7244 MEDIUM 5.5 DOWNGRADE The _pcre32_xclass function in pcre_xclass.c in libpcre1 in PCRE 8.40 allows remote attackers to cause a denia

References

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