CVE-2021-3156 · cross-distro fix matrix

CVE-2021-3156: Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which allows privilege escalation to root via "sudoedit -s" and a command-line argument that ends with a single backslash character.

Affects 8 Linux releases across 8 (distro × package) combinations.

Actively exploited in the wild

CVE-2021-3156 is on the CISA Known Exploited Vulnerabilities catalog (added 2022-04-06)— meaning attackers have a working exploit and are using it now. This is a patch-tonight, not patch-someday.

EPSS:99% · 30-day exploit probability100th percentile

Fix per ecosystem

Each block below is a distro release where CVE-2021-3156 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

sudo→ fixed in1.9.5p1-1.1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y sudo
```

Debian bookworm

Source: Debian Security Tracker

sudo→ fixed in1.9.5p1-1.1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y sudo
```

Debian trixie

Source: Debian Security Tracker

sudo→ fixed in1.9.5p1-1.1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y sudo
```

Alpine v3.20

Source: Alpine secdb

sudo→ fixed in1.9.5_p2-r0
```
apk update && apk add --upgrade sudo
```

Alpine v3.21

Source: Alpine secdb

sudo→ fixed in1.9.5_p2-r0
```
apk update && apk add --upgrade sudo
```

Alpine edge

Source: Alpine secdb

sudo→ fixed in1.9.5_p2-r0
```
apk update && apk add --upgrade sudo
```

Alpine v3.18

Source: Alpine secdb

sudo→ fixed in1.9.5p2-r0
```
apk update && apk add --upgrade sudo
```

Alpine v3.19

Source: Alpine secdb

sudo→ fixed in1.9.5_p2-r0
```
apk update && apk add --upgrade sudo
```

Are YOU affected by CVE-2021-3156?

5-second check on your actual server. Reads /etc/os-release, uname -r, and the distro's package manager; matches against this same cross-source index live.

curl https://mindsparkstack.com/scan.sh | bash

Form-based quickscan View on NVD

Continuous monitoring beats manual checking

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