CVE-2015-7802: gifread.c in gif2png, as used in OptiPNG before 0.7.6, allows remote attackers to cause a denial of service (u

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MEDIUM 5.5WATCHLISTDOWNGRADEMITIGATE

CVE-2015-7802 is a medium-severity flaw (CVSS 5.5) affecting optipng, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

gifread.c in gif2png, as used in OptiPNG before 0.7.6, allows remote attackers to cause a denial of service (uninitialized memory read) via a crafted GIF file.

Why this priority

On your watchlist

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.6% (top 25%)
CISA exploited list	No
Weakness	CWE-119
Published	2016-04-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: canonical · optipng project

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

Am I affected?

Timeline

2016-04-20 16:59 UTCPublished CVE record published
2026-06-17 00:33 UTCUpdated Record last modified

optipng project optipng DOWNGRADE

Affected: 0.7.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.7.5

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.7.5 (Debian / Ubuntu)

apt-cache madison optipng sudo apt install optipng=<VERSION_BEFORE_0.7.5> sudo apt-mark hold optipng

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

dnf --showduplicates list optipng sudo dnf downgrade optipng-<VERSION_BEFORE_0.7.5> sudo dnf versionlock add optipng

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.

canonical ubuntu linux MITIGATE

Affected: 12.04 · 14.04 · 15.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 12.04

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.

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-2015-7802?

optipng: downgrade or apply the listed mitigation; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2015-7802 being exploited?

CVE-2015-7802 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-2015-7802 affect?

CVE-2015-7802 affects optipng, ubuntu linux. Severity is medium (CVSS 5.5). gifread.c in gif2png, as used in OptiPNG before 0.7.6, allows remote attackers to cause a denial of service (uninitialized memory read) via a crafted GIF file.

How urgent is CVE-2015-7802?

Priority 43/100. On your watchlist

Software pages

Ubuntu vulnerabilities

Related CVEs

CVE-2023-43907 HIGH 7.8 DOWNGRADE OptiPNG v0.7.7 was discovered to contain a global buffer overflow via the 'buffer' variable at gifread.c.
CVE-2017-16938 HIGH 7.8 DOWNGRADE A global buffer overflow in OptiPNG 0.7.6 allows remote attackers to cause a denial-of-service attack or other
CVE-2017-1000229 HIGH 7.8 DOWNGRADE MITIGATE Integer overflow bug in function minitiff_read_info() of optipng 0.7.6 allows an attacker to remotely execute
CVE-2016-3982 HIGH 8.8 MITIGATE MITIGATE Off-by-one error in the bmp_rle4_fread function in pngxrbmp.c in OptiPNG before 0.7.6 allows remote attackers
CVE-2016-3981 HIGH 7.8 UPGRADE MITIGATE Heap-based buffer overflow in the bmp_read_rows function in pngxrbmp.c in OptiPNG before 0.7.6 allows remote a

References

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