CVE-2017-5375: JIT code allocation can allow for a bypass of ASLR and DEP protections leading to potential memory corruption

Q: How do I fix CVE-2017-5375?

enterprise linux desktop: mitigate or apply the listed mitigation; enterprise linux server: mitigate or apply the listed mitigation; enterprise linux workstation: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2017-5375 being exploited?

CVE-2017-5375 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-2017-5375 affect?

CVE-2017-5375 affects enterprise linux desktop, enterprise linux server, enterprise linux workstation. Severity is critical (CVSS 9.8). JIT code allocation can allow for a bypass of ASLR and DEP protections leading to potential memory corruption attacks. This vulnerability affects Thunderbird < 45.7, Firefox ESR < 45.7, and Firefox < 51.

Q: How urgent is CVE-2017-5375?

Priority 74/100. Critical severity; EPSS top 2%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTMITIGATEMITIGATEMITIGATE

CVE-2017-5375 is a critical-severity flaw (CVSS 9.8) affecting enterprise linux desktop, enterprise linux server, enterprise linux workstation. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

JIT code allocation can allow for a bypass of ASLR and DEP protections leading to potential memory corruption attacks. This vulnerability affects Thunderbird < 45.7, Firefox ESR < 45.7, and Firefox < 51.

Why this priority

Critical severity
EPSS top 2%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

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	34.1% (top 2%)
CISA exploited list	No
Weakness	CWE-119
Published	2018-06-11
Last modified	2026-06-17

Publisher (CNA): Mozilla Corporation · Vendor: debian · mozilla · redhat

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

Am I affected?

Timeline

2018-06-11 21:29 UTCPublished CVE record published
2026-06-17 01:20 UTCUpdated Record last modified

redhat enterprise linux desktop MITIGATE

Affected: 5.0 · 6.0 · 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat enterprise linux server MITIGATE

Affected: 5.0 · 6.0 · 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat enterprise linux workstation MITIGATE

Affected: 5.0 · 6.0 · 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mozilla firefox UPGRADE

Affected: < 45.7.0 · < 51.0.1

Fixed in: 45.7.0, 51.0.1

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 45.7.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade firefox

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade firefox

Note

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

mozilla thunderbird UPGRADE

Affected: < 45.7.0

Fixed in: 45.7.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 45.7.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade thunderbird

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade thunderbird

Note

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

debian debian linux MITIGATE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · librepo · FIXED · 1.21.3-1.fc46 · FEDORA-2026-c502136ca7 · source

sudo dnf upgrade --advisory=FEDORA-2026-c502136ca7

Debian 12 · firefox-esr · FIXED · 45.7.0esr-1

sudo apt update && sudo apt install --only-upgrade firefox-esr dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "45.7.0esr-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · firefox-esr · FIXED · 45.7.0esr-1

sudo apt update && sudo apt install --only-upgrade firefox-esr dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "45.7.0esr-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 5 · firefox · FIXED · firefox-45.7.0-2.el5_11

sudo dnf upgrade --advisory=RHSA-2017:0190 rpm -q firefox

RHEL 5 · thunderbird · FIXED · thunderbird-45.7.0-1.el5_11

sudo dnf upgrade --advisory=RHSA-2017:0238 rpm -q thunderbird

RHEL 6 · firefox · FIXED · firefox-45.7.0-2.el6_8

sudo dnf upgrade --advisory=RHSA-2017:0190 rpm -q firefox

RHEL 6 · thunderbird · FIXED · thunderbird-45.7.0-1.el6_8

sudo dnf upgrade --advisory=RHSA-2017:0238 rpm -q thunderbird

RHEL 7 · firefox · FIXED · firefox-45.7.0-2.el7_3

sudo dnf upgrade --advisory=RHSA-2017:0190 rpm -q firefox

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: bugzilla.mozilla.org/show_bug.cgi?id=1325200
Write-up: www.exploit-db.com/exploits/42327/
Write-up: www.exploit-db.com/exploits/44293/
Exploit-DB: Firefox 44.0.2 - ASM.JS JIT-Spray Remote Code Execution
Exploit-DB: Firefox 46.0.1 - ASM.JS JIT-Spray Remote Code Execution
Exploit-DB: Firefox 50.0.1 - ASM.JS JIT-Spray Remote Code Execution

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-2017-5375?

enterprise linux desktop: mitigate or apply the listed mitigation; enterprise linux server: mitigate or apply the listed mitigation; enterprise linux workstation: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2017-5375 being exploited?

CVE-2017-5375 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-2017-5375 affect?

CVE-2017-5375 affects enterprise linux desktop, enterprise linux server, enterprise linux workstation. Severity is critical (CVSS 9.8). JIT code allocation can allow for a bypass of ASLR and DEP protections leading to potential memory corruption attacks. This vulnerability affects Thunderbird < 45.7, Firefox ESR < 45.7, and Firefox < 51.

How urgent is CVE-2017-5375?

Priority 74/100. Critical severity; EPSS top 2%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities · Mozilla Firefox vulnerabilities · Mozilla Thunderbird vulnerabilities

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References

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