How severe is CVE-2026-34757?

CVE-2026-34757 has a CVSS 3.x base score of 5.1, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-34757 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34757?

CVE-2026-34757 primarily affects Libpng. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-34757?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-34757 have an EU (EUVD) identifier?

Yes. CVE-2026-34757 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20897.

When was CVE-2026-34757 published?

CVE-2026-34757 was published on 2026-04-09 and last updated on 2026-06-17.

CVE-2026-34757

CVE-2026-34757 is a medium-severity vulnerability in Libpng with a CVSS 3.x base score of 5.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Severity: Medium (CVSS 3.x base score 5.1)
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20897
Weakness: CWE-416
Affected product: Libpng
Published: 2026-04-09
Last modified: 2026-06-17

Description

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From 1.0.9 to before 1.6.57, passing a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_hIST back into the corresponding setter on the same png_struct/png_info pair causes the setter to read from freed memory and copy its contents into the replacement buffer. The setter frees the internal buffer before copying from the caller-supplied pointer, which now dangles. The freed region may contain stale data (producing silently corrupted chunk metadata) or data from subsequent heap allocations (leaking unrelated heap contents into the chunk struct). This vulnerability is fixed in 1.6.57.

Frequently asked questions

What is CVE-2026-34757?: LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From 1.0.9 to before 1.6.57, passing a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_hIST back into the corresponding setter on the same png_struct/png_info pair causes the setter to read from freed memory and copy its contents into the replacement buffer. The setter frees the internal buffer before copying from the caller-supplied pointer, which now dangles. The freed region may contain stale data (producing silently corrupted chunk metadata) or data from subsequent heap allocations (leaking unrelated heap contents into the chunk struct). This vulnerability is fixed in 1.6.57.
How severe is CVE-2026-34757?: CVE-2026-34757 has a CVSS 3.x base score of 5.1, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-34757 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34757?: CVE-2026-34757 primarily affects Libpng. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-34757?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34757 have an EU (EUVD) identifier?: Yes. CVE-2026-34757 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20897.
When was CVE-2026-34757 published?: CVE-2026-34757 was published on 2026-04-09 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:libpng:libpng:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

More vulnerabilities in Libpng

CVE-2017-12652 — Critical (CVSS 9.8): libpng before 1.6.32 does not properly check the length of chunks against the user limit.
CVE-2010-1205 — Critical (CVSS 9.8): Buffer overflow in pngpread.c in libpng before 1.2.44 and 1.4.x before 1.4.3, as used in progressive applications,…
CVE-2018-14550 — High (CVSS 8.8): An issue has been found in third-party PNM decoding associated with libpng 1.6.35. It is a stack-based buffer overflow…
CVE-2015-8540 — High (CVSS 8.8): Integer underflow in the png_check_keyword function in pngwutil.c in libpng 0.90 through 0.99, 1.0.x before 1.0.66,…
CVE-2015-0973 — High (CVSS 8.8): Buffer overflow in the png_read_IDAT_data function in pngrutil.c in libpng before 1.5.21 and 1.6.x before 1.6.16 allows…
CVE-2014-9495 — High (CVSS 8.8): Heap-based buffer overflow in the png_combine_row function in libpng before 1.5.21 and 1.6.x before 1.6.16, when…

All CVEs affecting Libpng →

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