CVE-2023-4911
HighExploitedPublic exploitA buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable.
Published Oct 3, 2023 · Updated Oct 16, 2026 · Also known as DEBIAN-CVE-2023-4911, DSA-5514-1, Looney Tunable, Looney Tunables, UBUNTU-CVE-2023-4527, UBUNTU-CVE-2023-4911, USN-6409-1
Key Facts
Patch immediately- CVE-2023-4911 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting Glibc (Gnu), Ontap Select Deploy Administration Utility (Netapp), Codeready Linux Builder (Redhat) and 22 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Nov 3, 2023 and is known to be used in ransomware campaigns. Public exploit code is available.
- EPSS estimates a 64% probability of exploitation in the next 30 days.
- Fixed versions are available, including compat-libpthread-nonshared 2:2.28-225.0.4.ksplice1.el8, compat-libpthread-nonshared 2:2.28-225.0.4.ksplice1.el8_8.6, compat-libpthread-nonshared 2.28-225.0.4.el8.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
64%
Higher than 99.2% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings, used by ransomware
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2023-4911 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBC_TUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Nov 21, 2023 | Dec 12, 2023 | Not reported |
| Industry KEV feed | Nov 3, 2023 | Dec 12, 2023 | Known |
| CIRCL KEV | Nov 21, 2023 | Dec 12, 2023 | Not reported |
| ENISA EUVD | Nov 21, 2023 | n/a | Not reported |
Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Affected Products
806 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| GlibcGnu | >= 2.34 | 2.39 |
| Ontap Select Deploy Administration UtilityNetapp | See advisory | n/a |
| Codeready Linux BuilderRedhat | 9.0 | n/a |
| Codeready Linux Builder EusRedhat | 8.6, 9.2, 9.4, 9.6 | n/a |
| Codeready Linux Builder For Arm64Redhat | 9.0_aarch64 | n/a |
Patched Releases
compat-libpthread-nonshared
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6
Glibc
0:2.28-225.el8_8.6, 0:2.34-60.el9_2.7, 2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.12-1.212.el6_10.3+sp999, 2.17-326.el7_9.3+sp999, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.28-225.el8_8.6, 2.28-251.el8_10.11+sp999, 2.31-13+deb11u11+sp999, 2.31-13+deb11u7, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7, 2.34-60.el9_2.7, 2.35-0ubuntu3.4, 2.35-5, 2.36-8.ph5, 2.36-9+deb12u3, 2.37-12, 2.38-1ubuntu6, 2.38-4.1, 2.38-6, 2.38-r5, 2.39, NA
glibc-2.34
2.34-r0
glibc-all-langpacks
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-benchtests
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-common
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-devel
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7, 2.36-8.ph5, 2.38-4.1, NA
glibc-devel-static
2.38-4.1
glibc-doc
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-extra
2.38-4.1
glibc-gconv-extra
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-headers
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-headers-x86
2.34-52.amzn2023.0.6
glibc-html
2.38-4.1
glibc-i18n
2.36-8.ph5, NA
glibc-i18ndata
2.38-4.1
glibc-iconv
2.36-8.ph5, NA
glibc-info
2.38-4.1
glibc-lang
2.36-8.ph5, 2.38-4.1, NA
glibc-langpack-aa
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-langpack-af
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-langpack-agr
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-langpack-ak
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-langpack-am
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
glibc-langpack-an
2:2.28-225.0.4.ksplice1.el8, 2:2.28-225.0.4.ksplice1.el8_8.6, 2:2.34-60.0.3.ksplice1.el9, 2:2.34-60.0.3.ksplice1.el9_2.7, 2.28-225.0.4.el8, 2.28-225.0.4.el8_8.6, 2.34-52.amzn2023.0.6, 2.34-60.0.3.el9, 2.34-60.0.3.el9_2.7
Timeline
Publicly disclosed
Oct 3, 2023
Added to Industry KEV feed
Nov 3, 2023
Added to CISA KEV
Nov 21, 2023
Added to CIRCL KEV
Nov 21, 2023
Added to ENISA EUVD
Nov 21, 2023
Last updated
Oct 16, 2026
Weakness Type
- CWE-122 Heap-based Buffer Overflow
- CWE-787 Out-of-bounds Write
References
- advisoryRHSA-2023:5453
- advisoryRHSA-2023:5454
- advisoryRHSA-2023:5455
- advisoryRHSA-2023:5476
- advisoryRHSA-2024:0033
FAQ
Common Questions.
A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable.
Affected: Glibc (Gnu) versions >= 2.34; Ontap Select Deploy Administration Utility (Netapp); Codeready Linux Builder (Redhat) versions 9.0, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Nov 3, 2023 and is known to be used in ransomware campaigns.
Yes. It was added on Nov 21, 2023 with a federal remediation due date of Dec 12, 2023.
Public exploit code is available.
Fixed versions are available, including compat-libpthread-nonshared 2:2.28-225.0.4.ksplice1.el8, compat-libpthread-nonshared 2:2.28-225.0.4.ksplice1.el8_8.6, compat-libpthread-nonshared 2.28-225.0.4.el8.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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